os
1[ os ]
/ ɒs /
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noun, plural os·sa [os-uh]. /ˈɒs ə/.
Anatomy, Zoology. a bone.
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Origin of os
1First recorded in 1540–50; from Latin os (inflectional stem oss- ) “bone”
Other definitions for os (2 of 9)
os2
[ os ]
/ ɒs /
noun, plural o·ra [awr-uh, ohr-uh]. /ˈɔr ə, ˈoʊr ə/.
Anatomy, Zoology. a mouth or orifice of the body.
Origin of os
2First recorded in 1730–40; from Latin ōs (inflectional stem ōr- ) “mouth”
Other definitions for os (3 of 9)
os3
[ ohs ]
/ oʊs /
noun, plural o·sar [oh-sahr]. /ˈoʊ sɑr/.
Geology. an esker, especially when of great length.
Origin of os
3First recorded in 1840–50 as osar (plural); from Swedish ås (plural åsar ) “ridge (of a hill),” from Old Norse áss “thick pole or main beam; rocky ridge”
Other definitions for os (4 of 9)
Os
Symbol, Chemistry. osmium.
Other definitions for os (5 of 9)
Other definitions for os (6 of 9)
o/s
(of the calendar) Old Style.
out of stock.
(in banking) outstanding.
Other definitions for os (7 of 9)
O/S
(of the calendar) Old Style.
Other definitions for os (8 of 9)
O.S.1
or o.s.
abbreviation
(in prescriptions) the left eye.
Origin of O.S.
1From Latin oculus sinister
Other definitions for os (9 of 9)
O.S.2
abbreviation
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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022
How to use os in a sentence
British Dictionary definitions for os (1 of 6)
Word Origin for os
C16: from Latin: bone; compare Greek osteon
British Dictionary definitions for os (2 of 6)
os2
/ (ɒs) /
noun plural ora (ˈɔːrə)
anatomy zoology a mouth or mouthlike part or opening
Word Origin for os
C18: from Latin
British Dictionary definitions for os (3 of 6)
Word Origin for os
C19 osar (pl), from Swedish ås (sing) ridge
British Dictionary definitions for os (4 of 6)
Os
the chemical symbol for
osmium
British Dictionary definitions for os (5 of 6)
OS
abbreviation for
Old School
Old Style (method of reckoning dates)
Ordinary Seaman
(in Britain) Ordnance Survey
outsize
Old Saxon (language)
British Dictionary definitions for os (6 of 6)
o.s.
OS or O/S
abbreviation for
out of stock
banking outstanding
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Medical definitions for os (1 of 4)
os 11
[ ŏs ]
n. pl. o•ra (ôr′ə)
An opening into a hollow organ or canal.
The oral cavity; mouth.
Medical definitions for os (2 of 4)
os 22
[ ŏs ]
n. pl. os•sa (ŏs′ə)
Bone.
Medical definitions for os (3 of 4)
Os
The symbol for the elementosmium
Medical definitions for os (4 of 4)
OS
abbr.
oculus sinister (left eye)
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Scientific definitions for os
Os
The symbol for osmium.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.