- 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)
WordReference Random House Unabridged Dictionary of American English © 2026
Ob
(ôb, ob; Russ. ôp),USA pronunciation n.
OB,
ob.,
- Place Namesa river in the W Russian Federation in Asia, flowing NW to the Gulf of Ob. 2500 mi. (4025 km) long.
- Place Names Gulf of, an inlet of the Arctic Ocean. ab. 500 mi. (800 km) long.
OB,
- PathologyAlso, ob [Med.]
- obstetrical.
- obstetrician.
- obstetrics.
- Show Businessoff Broadway.
- opening of books.
- ordered back.
- a prefix meaning "toward,'' "to,'' "on,'' "over,'' "against,'' orig. occurring in loanwords from Latin, but now used also, with the sense of "reversely,'' "inversely,'' to form Neo-Latin and English scientific terms:object;obligate;oblanceolate.
- Neo-Latin, Latin ob-
- Latin, representing ob (preposition); in some scientific terms,
- Old French)
- Middle English (
ob.,
- he died;
she died. -
Latin obiit - incidentally.
-
Latin obiit - oboe.
- Meteorologyobservation.
- opening of books.
- ordered back.
Collins Concise English Dictionary © HarperCollins Publishers::
Ob /Russian: ɔpj/ n
ob-, prefix.
- ob- is attached to roots and means "toward,'' "to,'' "on,'' "over,'' "against'':object, obligate.
Collins Concise English Dictionary © HarperCollins Publishers::
OB Brit abbreviation for
- Old Boy
- outside broadcast
Collins Concise English Dictionary © HarperCollins Publishers::
ob- prefix
- inverse or inversely: obovate
Collins Concise English Dictionary © HarperCollins Publishers::
ob. abbreviation for
- (on tombstones) obiit
- obiter
- oboe
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'Ob' also found in these entries (note: many are not synonyms or translations):
Aube
- Barnaul
- Irtysh
- Novosibirsk
- ob.
- ob-
- obdurate
- obese
- obey
- obfuscate
- obituary
- object
- objurgate
- oblate
- oblige
- obliterate
- oblong
- obloquy
- obnoxious
- obsequious
- observe
- obsess
- obsolete
- obstacle
- obstinate
- obstreperous
- obstruct
- obtain
- obtrude
- obtund
- obverse
- obvious
- occasion
- occiput
- occlude
- occult
- occupy
- occur
- offend
- offer
- omit
- opponent
- opportune
- oppose
- oppress
- opprobrium
- oppugn
- ostensible
- bisk
- blue stellar object
