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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 one day they told her to stick with Ob.

From "Missing May" by Cynthia Rylant

The documentation showed OB Projects' letter of engagement addressed to Mercury partner Bryan Lanza, a Republican strategist and former Trump elections campaign communications director.

From BBC ● Mar. 14, 2026

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

Vaughn, a D.C. correspondent for the business network since 2016, was told during a routine OB appointment that it was baby time, she told People exclusively.

From Los Angeles Times ● Apr. 24, 2025

Around 9:30 a.m., the OB on duty, Dr. Marcelo Totorica, couldn’t find a fetal heart rate, according to records; he told the family he was sorry for their loss.

From Salon ● Nov. 1, 2024

Bisect the chord PB at G, and draw through G a line perpendicular to PB, intersecting BB′ in O. An arc with centre O and radius OB forms part of a curve.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various

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

From Time Magazine Archive

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

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

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

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

It cameto pass morning very snare the ob. to seehis own arrived 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

I am, sir, Your most ob. serv't, Wm.

From Tea Leaves Being a Collection of Letters and Documents relating to the shipment of Tea to the American Colonies in the year 1773, by the East India Tea Company. (With an introduction, notes, and biographical notices of the Boston Tea Party) by Francis S. (Francis Samuel) Drake

Near the site of this ancient sanctuary stood a tomb, inscribed, 'John Michael Brown, ob. 15th December, A. D. 1750.

From Irish Race in the Past and the Present by Augustus J. Thebaud

Man'dĕ -ʞaⁿ ¢aⁿ ukínacke gaxá- biamá, kĭ síg¢e ¢é -hnaⁿ tĕ ĕ'di i¢aⁿ'¢a- bow string the ob. noose he made it they say, and trail went habitually the there he put it biamá.

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

Gornicki, ob. after 1591, Czarnkowski, Odachowski, and others, but especially the first named, were considered as the most distinguished orators of the age.

From Historical View of the Languages and Literature of the Slavic Nations by Therese Albertine Louise von Jacob Robinson

Sarah Finn, the casting director on “Loki” who also worked on “Everything Everywhere,” recommended Quan for the role of O.B. after seeing the film at a cast and crew screening.

From Los Angeles Times ● Nov. 27, 2023

Another O.B. quote from “Science/Fiction” speaks to this: the company’s ills were, and are, a fiction problem – in that Marvel it bent on pushing out too much of it that isn’t worth our attention.

From Salon ● Nov. 9, 2023

Jackson city council members voted Thursday to hire contract workers from a Los Angeles-based company to staff the O.B.

From Seattle Times ● Nov. 10, 2022

Adding to the system’s problems, late August brought days of heavy rains and flooding in central Mississippi, and the O.B.

From New York Times ● Sep. 16, 2022

For the sake of formally acknowledging this debt, I will not endeavor to discuss here the careers of George Templeton Strong, Arthur 446 Bird, or O.B.

From Contemporary American Composers Being a Study of the Music of This Country, Its Present Conditions and Its Future, with Critical Estimates and Biographies of the Principal Living Composers; and an Abundance of Portraits, Fac-simile Musical Autographs, and Compositions by Rupert Hughes

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