Words that start with O
Once upon a time
"Once upon a time" signifies the beginning of a fairy tale or story fi...
Once-over
A once-over refers to a quick and superficial examination or assessmen...
Once-over-lightly
"Once-over-lightly" means to quickly skim or glance over something wit...
Oncer
A oncer is a person who watches a show or movie just once and does not...
Onchocerciasis
Onchocerciasis, also known as river blindness, is a parasitic disease ...
Oncidium
Oncidium is a genus of orchids known for their vibrant and showy flo...
Onco-
The prefix onco- refers to something related to tumors or cancer....
Oncogene
An oncogene is a gene that has the potential to cause cancer when muta...
Oncogenesis
Oncogenesis is the process by which normal cells transform into cancer...
Oncogenic
The term oncogenic refers to genes that have the potential to cause ca...
Oncogenicity
Oncogenicity refers to the ability of a substance to cause cancer....
Oncolite
An oncolite is a fossilized structure formed by the precipitation of m...
Oncology
Oncology is the branch of medicine focused on the diagnosis, treatment...
Oncoming
The oncoming traffic was getting closer and closer, making the driver ...
Oncornavirus
Oncornavirus is a term referring to a virus that can potentially cause...
Oncost
The meaning of oncost can be described as the additional costs incurre...
OND
OND stands for Ordinary National Diploma, which is an academic qualifi...
Ondaatje
Ondaatje is a celebrated author whose writing is characterized by its ...
Ondes Martenot
The ondes Martenot is an early electronic musical instrument known for...
Ondine
Ondine is about a water nymph who loses her ability to breathe after f...
Onding
Onding refers to the process of connecting or joining two things toget...
Ondo
Ondo is a traditional dance from Nigeria that is performed during cult...
Ondograph
An ondograph is a graph that displays changes in sea level over time....
One
A single existence or entity....
One and all
The phrase "one and all" means everyone or every single person without...
One and only
"One and only" means that there is unique and singularly special....
One and the same
"One and the same" means identical or one in the same way....
One another
The phrase "one another" signifies mutual respect and consideration be...
One by one
"One by one" means individually or sequentially, one after the other....
One eye on
One eye on focuses on a single task or goal while still being aware of...
One fell swoop, in
"One fell swoop" means doing something all at once or in a single acti...
One foot in the grave, have
One foot in the grave means being close to death or in a very precario...
One for the books
"One for the books" means a noteworthy or memorable event that is unfo...
One for the road
"One for the road" means having one final drink before leaving a place...
One good turn deserves another
One good turn done for someone should be repaid with a similar kind ac...
One if by land, and two if by sea
The phrase "One if by land, and two if by sea" signifies the method of...
One in a million
One in a million means something is extremely rare or unique....
One jump ahead
One jump ahead means to be ahead in a situation or to be one step ahea...
One man's meat is another man's poison
One's meat can be another's poison means that what is enjoyable or ben...
One of a kind
One of a kind means unique, unmatched or unparalleled....
One of these days
One of these days, soon you will achieve your dreams and goals....
One of those days
"One of Those Days" highlights the challenges of dealing with difficul...
One old cat
One old cat symbolizes wisdom and experience gained over time....
One on, that's
The meaning of one on is to be in agreement or conformity with a parti...
One picture is worth a thousand words
One picture is worth a thousand words because it can convey complex em...
One rotten (or bad) apple spoils the barrel
One rotten (or bad) apple spoils the barrel means that one negative or...
One that loved not wisely but too well
One that loved not wisely but too well means loving intensely and pass...
One Thousand Guineas
"The meaning of One Thousand Guineas can be summed up as a prestigious...
One up
To have an advantage or be superior in a particular situation, outdoin...
One way or another
One way or another means somehow or in one of many possible ways....
One-a-cat
One-a-cat means playing a game of tag with only one cat involved....
One-acter
A one-acter is a dramatic play that consists of only one act....
One-armed bandit
A one-armed bandit refers to a type of mechanical slot machine typical...
One-bagger
A one-bagger refers to a baseball player who is capable of hitting a s...
One-base hit
A one-base hit refers to a batter successfully reaching first base aft...
One-dimensional
A system or object that only has one measurable dimension or aspect, l...
One-down
"Being inferior or at a disadvantage compared to someone or something ...
One-drop rule
The one-drop rule is a social and legal principle in the United States...
One-eighty
A complete change in direction or attitude, often unexpectedly or dram...
One-eyed
Having only one functioning eye or missing an eye altogether....
One-handed
Having only one functioning hand or arm being able to perform tasks wi...
One-horse
"one-horse" is a term used to describe something small or insignifican...
One-horse town
A one-horse town refers to a small, insignificant place with very few ...
One-legged
"One-legged" means having only one functional leg, limb, or appendage....
One-liner
A one-liner is a concise joke or statement that is typically delivered...
One-lung
One-lung refers to a condition where a person has only one functioning...
One-lunger
The meaning of one-lunger is a small and inexpensive single-cylinder e...
One-man
The meaning of one-man is pertaining to or involving only one person....
One-man show
A one-man show is a performance in which a solo artist takes the stage...
One-many
One-many means a relationship where one element of a set can be associ...
One-night stand
A one-night stand is a casual sexual encounter between two people with...
One-nighter
A one-nighter is a brief romantic or sexual encounter lasting only for...
One-note
One-note means to focus on one idea or theme without much variation or...
One-off
A one-off refers to something that is unique or done only once....
One-on-one
One-on-one means a meeting or interaction that involves only two peopl...
One-one
One-one means that each element in the domain of a function is associa...
One-parent family
A one-parent family consists of a single parent caring for one or more...
One-piece
"One-piece" refers to a garment that covers the entire body in one sin...
One-reeler
One-reeler refers to a short film that is typically brief and lasts fo...
One-shot
A "one-shot" refers to a story that is told in a single installment, w...
One-sided
One-sided means favoring one side or party over another in a biased wa...
One-size-fits-all
"One-size-fits-all" means that a product or solution is designed to be...
One-spot
One-spot refers to precision or accuracy in a particular location or i...
One-star
The meaning of one-star can be summarized as poor, indicating the lowe...
One-step
A one-step process involves completing a task in a single action or ph...
One-stop
A one-stop shop or service provides all necessary resources or solutio...
One-suiter
A one-suiter refers to a player's hand in bridge that consists mainly ...
One-tailed
One-tailed indicates a directional relationship between variables, wit...
One-time
"One-time" means something that occurs only once and does not repeat....
One-to-one
One-to-one means a direct relationship where each element in one set c...
One-track
One-track means narrowly focused or limited in perspective....
One-track mind
A one-track mind is characterized by a singular focus or obsession wit...
One-trick pony
A one-trick pony is someone or something that has only one skill or ta...
One-two
One-two is a term used in sports to describe a quick sequence of passe...
One-upmanship
One-upmanship is the practice of continually trying to outdo others in...
One-way
One-way means unidirectional, indicating movement or traffic flowing i...
One-way mirror
A one-way mirror is a specialized mirror that is partially reflective ...
One-way ticket
A one-way ticket refers to a travel document that allows a passenger t...
One-woman
The term "one-woman" signifies a solo individual taking on a task or r...
One-worlder
One who believes in the concept of unity and interconnectedness among ...
Onefold
Onefold means single or singular, representing unity or simplicity....
Oneg Shabbat
Oneg Shabbat is the celebration of Shabbat through joyful activities a...
Onega
Onega is a lake in northwestern Russia known for its crystal-clear wat...
Onega Bay
Onega Bay is a majestic inlet in northwestern Russia's White Sea....
Oneida
Oneida represents unity through community and shared beliefs....
Oneida Community
The Oneida Community was a utopian religious commune founded in the Un...
Oneida Lake
Oneida Lake is a large lake located in central New York....
Oneiric
Oneiric refers to something related to dreams or dreamlike states, oft...
Oneiro-
The prefix oneiro- pertains to dreams or dreaming....
Oneirocritic
A oneirocritic is someone who interprets dreams to uncover hidden mean...
Oneirocriticism
Oneirocriticism is the interpretation of dreams to uncover hidden mean...
Oneiromancy
Oneiromancy is the art of predicting the future through the interpreta...
Oneness
Oneness is the state of being unified or forming a complete whole....
Oneonta
Oneonta is a city in New York known for its picturesque surroundings a...
Oner
The word oner means someone who is extremely unique or extraordinary i...
Onerous
The term "onerous" means something that involves burdensome obligati...
Oneself
The self represents one's individuality, identity, and essence....
Onesie
A onesie is a one-piece garment for an infant or toddler, typically ma...
Onetti
Onetti's work is characterized by loneliness and existential themes....
ONFr.
The meaning of ONFr is "Official Languages of Canada in French."...
Ongaonga
Ongaonga means stinging nettle in Maori....
Ongoing
Ongoing means continuing without a set end....
Ongoings
The ongoings refer to the current and continuous events or situations ...
ONI
ONI is a Japanese folklore creature known for its shapeshifting abilit...
Onie
The meaning of onie is uniqueness or individuality....
Onigiri
Onigiri is a Japanese rice ball wrapped in seaweed and usually fille...
Oniomania
Oniomania is characterized by an excessive and uncontrollable desire t...
Onion
An onion is a vegetable known for its pungent aroma and flavor when co...
Onion dome
An onion dome is a architectural feature characterized by its dome sha...
Onion fly
The onion fly is a pest that lays its eggs on onion plants, causing da...
Onion rings
Onion rings are a type of fried appetizer made from sliced onions dipp...
Onion snow
Onion snow refers to a late spring snowfall that mimics the appearan...
Onion weed
Onion weed is a type of plant that resembles an onion but is considere...
Onions
The poem "Onions" discusses the layers of emotions and experiences tha...
Onionskin
The meaning of onionskin is a thin translucent paper....
Onitsha
Onitsha is a city in Nigeria known for its bustling markets and vibran...
Onium compound
An onium compound is a positively charged ion formed by the addition o...
Onkelos
Onkelos is a translator of the Hebrew Bible into Aramaic, known for hi...
Onkus
The meaning of onkus is a feeling of overwhelming doubt or uncertainty...
Onlap
Onlap is a geological term that refers to overlapping of sedimentary l...
Onlay
An onlay is a type of dental restoration that is placed over the cusp ...
Onliest
The word "onliest" means unique or one of a kind....
Online
The term online refers to being connected to the internet or available...
Online catalog
An online catalog is a digital database that allows users to browse an...
Online dictionary
An online dictionary is a digital resource that provides definitions, ...
Online thesaurus
An online thesaurus is a tool that provides synonyms and antonyms for ...
Onliner
An onliner is a short and impactful sentence that conveys a message ef...
Onload
The onload event occurs when a webpage has finished loading....
Onlooker
An onlooker is someone who observes a situation without actively parti...
Onlooking
The meaning of onlooking is to observe or watch something without part...
Only
The meaning of a sentence can be emphasized only through the strategic...
Only game in town, the
Only game in town means the exclusive or primary choice or option avai...
Only too
"Only too" means excessively or extremely, with emphasis on the word t...
Only-begotten
Only-begotten means having a unique origin or source....
Onnagata
Onnagata refers to male actors in Japanese kabuki theater who speciali...
Onomasiology
Onomasiology is the study of naming and categorization of concepts in ...
Onomastic
Onomastic is the study of names and their origins....
Onomasticon
An onomasticon is a list or dictionary of names, especially of places ...
Onomastics
Onomastics is the study of names and their origins, meanings, and usag...
Onomatology
Onomatology is the study of names, including their origins and meaning...
Onomatopoeia
Onomatopoeia is a word that imitates the natural sound of a thing or a...
Onondaga
Onondaga refers to the Iroquois Native American people and their langu...
Onondagan
Onondagan refers to a member of the Onondaga tribe, one of the six nat...
ONR
ONR stands for Office of Naval Research, a government agency responsib...
Onrush
The term "onrush" signifies a sudden and overwhelming flow or surge of...
ONS
ONS stands for the Office for National Statistics, a government agency...
Onsager
Onsager's contribution to physical chemistry was groundbreaking, with ...
Onset
The onset refers to the beginning or start of something, typically a p...
Onshore
"Onshore" refers to land-based activities or operations that occur wit...
Onshoring
Onshoring refers to the practice of bringing jobs and manufacturing ba...
Onside
"Onside" means that a player is in a position where they are not ahead...
Onside kick
An onside kick is a football strategy where the kicking team attempts ...
Onslaught
An onslaught refers to a fierce and intense attack or assault....
Onslow
Onslow is a character in the television show "Keeping Up Appearances" ...
Onstage
The term "onstage" refers to something that is happening on a stage, t...
Ont-
The meaning of ont- can be defined as being or existing....
Ontarian
An Ontarian is someone who is a resident of the Canadian province of O...
Ontario
Ontario is a province in Canada known for its diverse landscapes and v...
Ontic
The term ontic refers to the real and existing aspects of reality as o...
Onto
The term " onto" means covering or moving to a position on something....
Onto function
An onto function is a mapping where every element in the codomain is m...
Ontogeny
Ontogeny refers to the development and growth of an organism from conc...
Ontological
The ontological refers to the branch of metaphysics that deals with th...
Ontological argument
The ontological argument is a philosophical argument that attempts to ...
Ontologism
Ontologism is a philosophical doctrine that emphasizes the existence o...
Ontologize
Ontologize means to conceptualize or formalize a subject matter in ter...
Ontology
Ontology is the study of the nature of being and existence....
Onus
The onus refers to the responsibility or burden that falls on a partic...
Onus probandi
The onus probandi refers to the burden of proof that lies with the par...
Onward
The meaning of onward is to continue moving forward or ahead....
Onwards
"From this point onwards, we will only accept cash payments."...
Ony
The meaning of ony is only one or just one....
Onychia
Onychia is a condition characterized by inflammation or infection of t...
Onychophagia
Onychophagia is a nail-biting habit that can cause damage to the nails...
Onychophoran
The term onychophoran refers to a type of invertebrate animal commonly...
Onymous
The term onymous refers to something that is named or identified, as o...
Onyx
Onyx is a type of black stone known for its elegant appearance and pro...
Onyx marble
Onyx marble is a type of natural stone known for its striking veinin...
Onyxis
Onyxis refers to an inflammation of the nail bed....
ONZ
ONZ is a New Zealand governmental agency specializing in environmental...
OO gauge
OO gauge is a popular model railway scale where trains are scaled at 1...
Ooblast
The term ooblast refers to a primitive embryonic cell that eventually ...
Oocyst
An oocyst is a protective cyst containing fertilized eggs produced by ...
Oocyte
An oocyte is a female germ cell involved in reproduction, which mature...
Oodles
Oodles means a great quantity or amount....
Oof
Oof is an expression used to convey disappointment or sympathy....
Oogamete
An oogamete is a reproductive cell that fuses with another to form a z...
Oogamy
Oogamy is a type of reproduction where a large non-motile egg is ferti...
Oogenesis
Oogenesis is the process by which female gametes are produced in the o...
Oogonium
An oogonium is a structure in fungi and algae that produces female gam...
Ooh
The meaning of ooh can be described as an expression of surprise or ex...
Ookinesis
Ookinesis refers to movement that involves change in speed and directi...
Ookpik
Ookpik represents a symbol of the Arctic culture and a reminder of nat...
Oolachan
Oolachan, also known as "candlefish," holds significant cultural and e...
Oolite
Oolite is a type of sedimentary rock formed from small spherical gra...
Oolith
Oolith refers to a sedimentary rock formed from spherical grains or co...
Oology
The study of bird eggs, nests, and breeding behavior is known as oolog...
Oolong
Oolong is a partially oxidized tea with a complex flavor profile....
Oom
The term oom refers to one's grandmother or grandmother figure in Dutc...
Oom Paul
Oom Paul refers to an Afrikaans term for an elderly or respected man, ...
Oomiak
An oomiak is a large open boat used by the Inuit people for hunting an...
Oompah
Oompah is a style of music characterized by a bouncy and repetitive rh...
Oomph
Oomph is the extra energy or enthusiasm that adds excitement to someth...
Oomycete
Oomycetes are a group of eukaryotic microorganisms that are similar to...
Oomycota
Oomycota is a group of fungus-like organisms that are commonly referre...
Oona
"Oona is a story that explores the strength of a young girl's spirit i...
Oont
The oont represents a thick, shaggy-haired wild donkey found in Centra...
OOO
OOO stands for Out of Office, indicating that a person is unavailable ...
OOP
Object-oriented programming is a programming paradigm based on the con...
Oophorectomy
Oophorectomy is the surgical removal of one or both ovaries....
Oophoritis
Oophoritis is the inflammation of the ovaries, specifically the oophor...
Oophyte
An oophyte is a type of organism that reproduces asexually through the...
Oops
Oops is an interjection used to express a mild mistake or accident, of...
Oort
Oort is a theoretical region in the outermost part of the solar system...
Oort cloud
The Oort cloud is a theoretical cloud of icy objects located at the ou...
Oory
Oory means love or affection in the language of the fictional alien sp...
Oose
Oose refers to a thick, viscous substance or material....
Oosperm
The oosperm is the female reproductive cell that fuses with a male spe...
Oosphere
An oosphere is a female reproductive cell in certain algae and fungi....
Oospore
An oospore is a thick-walled sexual spore produced by some fungi and a...
Oost
Oost is a term that refers to the East, symbolizing a direction assoc...
Oostende
Oostende is a vibrant seaside city in Belgium known for its sandy beac...
OOT
OOT, or out of touch, refers to someone who is disconnected or uninfor...
Ootheca
An ootheca is a protective casing for insect eggs, often referred to a...
Ootid
Ootid refers to a developing egg cell in the final stage before becomi...
Ooze
Ooze refers to slowly flowing or seeping out in a thick, sticky manner...
Ooze leather
Ooze leather refers to a type of soft, supple leather that has been oo...
Oozy
The word "oozy" refers to something that is oozing or dripping slowly....
Op
OP, short for original poster, refers to the person who started a disc...
Op art
Op art is a visual art movement that uses optical illusions and geomet...
Op-Ed
An Op-Ed is an opinion piece written by someone not on the newspaper's...
Op-shop
An op-shop is a thrift store that sells second-hand goods at discounte...
Op. cit.
Op. cit. is an abbreviation for opus citatum, which means "work cited"...
OPA
OPA, also known as Other People's Approval, refers to seeking validati...
Opa-Locka
Opa-Locka is a city in Miami-Dade County known for its Arabesque archi...
Opacify
To opacify means to make something opaque or less transparent....
Opacity
Opacity refers to the obscuration or lack of transparency in a materia...
Opacus
Opacus means dark in Latin....
Opah
Opah is a type of fish characterized by its round shape and vibrant co...
Opal
Opal is a beautiful gemstone known for its unique play of colors....
Opal glass
Opal glass is a type of glass known for its milky or opaque appearance...
Opalesce
Opalesce means to exhibit a play of colors resembling that of an opal...
Opalescence
Opalescence refers to the iridescent quality of a surface that reflect...
Opalescent
Opalescent refers to an object or material having a milky, iridescent ...
Opaleye
The opaleye is a type of fish known for its iridescent, opalescent col...
Opaline
Opaline is a term used to describe something that resembles the iride...
Opaque
The term "opaque" refers to something that is not transparent and does...
Opaque context
Opaque context refers to a situation where information is unclear or o...
Opaque projector
An opaque projector is a device that enlarges and displays images from...
OPC
OPC, or Object Linking and Embedding (OLE) for Process Control, is a c...
Ope
Ope means to open or reveal, often by accident or surprise....
OPEC
The OPEC stands for the Organization of the Petroleum Exporting Countr...
Opechancanough
Opechancanough was a powerful Powhatan leader who led the Native Ameri...
Opelika
Opelika is a city in Alabama with a rich history and vibrant community...
Opelousas
Opelousas is a city in Louisiana that is known for its rich cultural h...
Open
The meaning of open is to allow access or passage....
Open account
An open account refers to a credit arrangement in which items are bill...
Open admissions
Open admissions means that a college or university accepts all student...
Open adoption
Open adoption involves sharing information between birth parents and a...
Open air
The open air refers to the outdoors or a space that is not enclosed by...
Open and aboveboard
To be open and aboveboard means to be honest and transparent, without ...
Open bar
An open bar means that guests can enjoy drinks without having to pay f...
Open book
Being transparent and receptive, like an open book, without hiding any...
Open Brethren
Open Brethren are a group of Christians who emphasize the importance o...
Open call
An open call refers to a broad invitation for participation or submiss...
Open caption
Open caption refers to subtitles that are always visible on the screen...
Open carry
Open carry refers to the practice of openly carrying a firearm in publ...
Open chain
Open chain refers to a molecule that does not form a continuous ring s...
Open cheque
An open cheque is a signed cheque that does not specify a payee, allow...
Open circuit
Open circuit is a situation where there is a break in the path of curr...
Open city
An open city is a place that does not engage in military defense and i...
Open classroom
Open classroom refers to a flexible educational environment where stud...
Open cluster
An open cluster is a group of stars that are loosely bound together by...
Open College
Open College is an institution that offers flexible education opportun...
Open communion
Open communion is the practice of allowing all baptized Christians to ...
Open convention
An open convention is a gathering where anyone can participate and hav...
Open couplet
An open couplet is a pair of rhyming lines that do not form a complete...
Open court
Open court means that judicial proceedings and trials are conducted pu...
Open cover
An open cover is a collection of sets that completely covers a space w...
Open dating
Open dating is a process that involves clearly marking products with e...