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  • Ob
    Ob
    noun
    a river in the W Russian Federation in Asia, flowing NW to the Gulf of Ob. 2,500 miles (4,025 km) long.
  • OB
    OB
    abbreviation
    Also ob
  • ob-
    ob-
    a prefix meaning “toward,” “to,” “on,” “over,” “against,” originally occurring in loanwords from Latin, but now used also, with the sense of “reversely,” “inversely,” to form New Latin and English scientific terms: object; obligate; oblanceolate.
  • ob.
    ob.
    abbreviation
    he died; she died.
  • O.B.
    O.B.
    abbreviation
    opening of books.

Ob

1 American  
[awb, ob, awp] / ɔb, ɒb, ɔp /

noun

  1. a river in the W Russian Federation in Asia, flowing NW to the Gulf of Ob. 2,500 miles (4,025 km) long.

  2. Gulf of, an inlet of the Arctic Ocean. About 500 miles (800 km) long.


OB 2 American  

abbreviation

  1. Medicine/Medical. Also ob

    1. obstetric.

    2. obstetrician.

    3. obstetrics.

  2. off Broadway.

  3. opening of books.

  4. ordered back.


ob- 3 American  
  1. a prefix meaning “toward,” “to,” “on,” “over,” “against,” originally occurring in loanwords from Latin, but now used also, with the sense of “reversely,” “inversely,” to form New Latin and English scientific terms: object; obligate; oblanceolate.


ob. 4 American  

abbreviation

  1. he died; she died.


ob. 5 American  

abbreviation

  1. incidentally.


ob. 6 American  

abbreviation

  1. oboe.

  2. Meteorology. observation.


O.B. 7 American  
Or O/B.

abbreviation

  1. opening of books.

  2. ordered back.


ob. 1 British  

abbreviation

  1. (on tombstones) obiit

  2. obiter

  3. oboe

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

OB 2 British  

abbreviation

  1. Old Boy

  2. outside broadcast

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Ob 3 British  
/ ɔpj /

noun

  1. a river in N central Russia, formed at Bisk by the confluence of the Biya and Katun Rivers and flowing generally north to the Gulf of Ob (an inlet of the Arctic Ocean): one of the largest rivers in the world, with a drainage basin of about 2 930 000 sq km (1 131 000 sq miles). Length: 3682 km (2287 miles)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

ob- 4 British  

prefix

  1. inverse or inversely

    obovate

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of ob-3

Middle English (from Old French ) from Latin, representing ob (preposition); in some scientific terms, from New Latin, Latin ob- (prefix)

Origin of ob.4

From the Latin word obiit

Origin of ob.5

From the Latin word obiter

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Water levels in both the Ishim and the Tobol, which form part of the world's seventh longest Ob river system, are not expected to peak until 23 or 24 April.

From BBC ● Apr. 16, 2024

All of this has a number of implications for the Arctic: northern rivers, especially the region's largest, the Ob, Yenesey, Lena and Mackenzie, will see proportionally more water coming from their northern reaches.

From Science Daily ● Mar. 5, 2024

Poor ol' RiP will try to buck the trend but, as Ob pointed out, it's one facade in public and another in private. 

From Time ● Apr. 30, 2013

‘They stand, and they withstand’: the nomadic Nenets photographed by Sebastião Salgado: north of the Ob river, inside the Arctic Circle, Yamal Peninsula, Siberia, 2011.

From The Guardian ● Apr. 13, 2013

And if Ob does go, goes off to be with May, then it’ll be just me and the whirligigs left.

From "Missing May" by Cynthia Rylant

I called my OB to check on the slightest twitch or pain at all times of day or night.

From The Wall Street Journal ● Oct. 23, 2025

Paul Barrow, 38, who plays on the wing for Collegiate OB, faced former Wigan full-back Figueroa on Sunday - and had to explain to his nine-year-old son who Heskey was.

From BBC ● Oct. 21, 2025

“It’s really hard to find an OB last minute, so they should try to utilize their OB-GYN’s network,” she said.

From Los Angeles Times ● Jan. 11, 2025

The next day, Dr. Shirley Lima, an OB on duty, diagnosed an “inevitable” miscarriage.

From Salon ● Oct. 30, 2024

OC is the axis xy whilst OA and OB are the traces of the third plane.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" by Various

Carter begins not only with that advantage but also, as an outsider, he is free of many heavy ob- ligations to special groups.

From Time Magazine Archive

A subscription of $1,000 was voted to help ob- tain a pardon for Mooney.

From Time Magazine Archive

This ob- noxious tonic possesses many of the vitamins necessary to discourage rickets, gives strength to rickety children.

From Time Magazine Archive

And in the opinion of Washington ob- servers he was not likely to compromise unless Recession grew even blacker.

From Time Magazine Archive

The school created the very first teaching hospital in the world, a place where the sick were treated and young doctors learned their craft, as well as a fine ob- servatory to track the heavens.

From "Sugar Changed the World: A Story of Magic, Spice, Slavery, Freedom, and Science" by Marc Aronson

Two pound of hennes flesh, geese, or ducke, is worth two foi of their money, that is, d. ob. sterling.

From The Principal Navigations, Voyages, Traffiques and Discoveries of the English Nation — Volume 11 by Richard Hakluyt

Here lyes the body of William Wheatley, ob. 10th Nov. 1683.

From William Shakespere, of Stratford-on-Avon His Epitaph Unearthed, and the Author of the Plays run to Ground by Scott Surtees

"I am, with sincere esteem, "Rev'd Sir, Y'r m. ob. & m. h.

From Literary Character of Men of Genius Drawn from Their Own Feelings and Confessions by Isaac Disraeli

Person the mv. ob. now I-first I go will I who, thought they say.

From Illustration Of The Method Of Recording Indian Languages From the First Annual Report of the Bureau of Ethnology, Smithsonian Institution by Albert Samuel Gatschet

St Bernard, 1091-1153; Bernard of Morlaix, exact years uncertain, but twelfth century; Adam of St Victor, ob. cir.

From The Flourishing of Romance and the Rise of Allegory (Periods of European Literature, vol. II) by George Saintsbury

He’s even wearing a pin of O.B. on his black jacket.

From Los Angeles Times ● Nov. 27, 2023

Some is attributable to Ke Huy Quan's onboarding as O.B., the TVA's hidden tech genius, and our reminder that not everything that happened to the multiverse between 2021 and now was terrible.

From Salon ● Oct. 5, 2023

Among seven water and sewer system upgrades, the funds will be used to help replace a raw water pump at the beleaguered O.B.

From Seattle Times ● Nov. 4, 2022

“You’ve been paying into Social Security your whole life,” Mr. Biden told an audience at O.B.

From New York Times ● Nov. 1, 2022

The extreme views of Baur and Zeller were interpreted by Rev. O.B.

From Unitarianism in America by George Willis Cooke

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