os

1
[ os ]

noun,plural os·sa [os-uh]. /ˈɒs ə/.
  1. Anatomy, Zoology. a bone.

Origin of os

1
First recorded in 1540–50; from Latin os (inflectional stem oss- ) “bone”

Other definitions for os (2 of 9)

os2
[ os ]

noun,plural o·ra [awr-uh, ohr-uh]. /ˈɔr ə, ˈoʊr ə/.
  1. Anatomy, Zoology. a mouth or orifice of the body.

Origin of os

2
First recorded in 1730–40; from Latin ōs (inflectional stem ōr- ) “mouth”

Other definitions for os (3 of 9)

os3
[ ohs ]

noun,plural o·sar [oh-sahr]. /ˈoʊ sɑr/.
  1. Geology. an esker, especially when of great length.

Origin of os

3
First 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

  1. Symbol, Chemistry. osmium.

Other definitions for OS (5 of 9)

OS

abbreviation
  1. Old Saxon. : Also O.S.

  2. Computers. operating system.

Other definitions for o/s (6 of 9)

o/s

  1. (of the calendar) Old Style.

  2. out of stock.

  1. (in banking) outstanding.

Other definitions for O/S (7 of 9)

O/S

  1. (of the calendar) Old Style.

Other definitions for O.S. (8 of 9)

O.S.1

abbreviation
  1. (in prescriptions) the left eye.

Origin of O.S.

8
From Latin oculus sinister

Other definitions for O.S. (9 of 9)

O.S.2

abbreviation
  1. Old Saxon. : Also OS

  2. (of the calendar) Old Style (def. 2).

  1. ordinary seaman. : Also o.s.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use os in a sentence

  • Had we not heard him say that the signal was to be an S O S sent, as it were, from the fleet far out on the ocean?

    The Social Gangster | Arthur B. Reeve

British Dictionary definitions for os (1 of 6)

os1

/ (ɒs) /


nounplural ossa (ˈɒsə)
  1. anatomy the technical name for bone

Origin of os

1
C16: from Latin: bone; compare Greek osteon

British Dictionary definitions for os (2 of 6)

os2

/ (ɒs) /


nounplural ora (ˈɔːrə)
  1. anatomy zoology a mouth or mouthlike part or opening

Origin of os

2
C18: from Latin

British Dictionary definitions for os (3 of 6)

os3

/ (əʊs) /


nounplural osar (ˈəʊsɑː)
  1. another name for esker

Origin of os

3
C19 osar (pl), from Swedish ås (sing) ridge

British Dictionary definitions for Os (4 of 6)

Os

the chemical symbol for
  1. osmium

British Dictionary definitions for OS (5 of 6)

OS

abbreviation for
  1. Old School

  2. Old Style (method of reckoning dates)

  1. Ordinary Seaman

  2. (in Britain) Ordnance Survey

  3. outsize

  4. Old Saxon (language)

British Dictionary definitions for o.s. (6 of 6)

o.s.

abbreviation for
  1. out of stock

  2. banking outstanding

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

Scientific definitions for Os

Os

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.