os

[ os ]

noun,plural os·sa

[os-uh]. /ˈɒs ə/.

Anatomy, Zoology. a bone.

Origin of os

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/.

Anatomy, Zoology. a mouth or orifice of the body.

Origin of os

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/.

Geology. an esker, especially when of great length.

Origin of os

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)

Symbol, Chemistry. osmium.

Other definitions for OS (5 of 9)

abbreviation

Old Saxon. : Also O.S.
Computers. operating system.

Other definitions for o/s (6 of 9)

o/s

(of the calendar) Old Style.
out of stock.

(in banking) outstanding.

Other definitions for O/S (7 of 9)

O/S

(of the calendar) Old Style.

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

O.S.¹

abbreviation

(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

Old Saxon. : Also OS
(of the calendar) Old Style (def. 2).

ordinary seaman. : Also o.s.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use os in a sentence

For the rest of the trip, Rizzo kept spelling out, in order, the letters r-h-i-n-o-c-e-r-o-s and a-n-t-h-r-o-p-o-i-d.
Portrait of the Consummate Con Man | John Lardner | May 17, 2014 | THE DAILY BEAST
To see us all here tonight, who would dream of the parting to come so soon-n; s-o s-o-o-o-on-n!
Marjorie Dean College Freshman | Pauline Lester
Mysteriously, without warning, they had vanished; without a single S O S being sent, seven freighters had been lost.
Astounding Stories of Super-Science, November, 1930 | Various
Dites suis-je seul avec mon me, Mon me hlas maison d'bne O s'est fendu sans bruit un soir Le grand miroir de mon espoir?
Modernities | Horace Barnett Samuel
Can you link the power, or whatever you call it, up with the sending paraphernalia and get an S O S over the water?
The Campfire Girls on Station Island | Margaret Penrose

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)

anatomy the technical name for bone

Origin of os

C16: from Latin: bone; compare Greek osteon

British Dictionary definitions for os (2 of 6)

os²

/ (ɒs) /

nounplural ora (ˈɔːrə)

anatomy zoology a mouth or mouthlike part or opening

Origin of os

C18: from Latin

British Dictionary definitions for os (3 of 6)

os³

/ (əʊs) /

nounplural osar (ˈəʊsɑː)

another name for esker

Origin of os

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

British Dictionary definitions for Os (4 of 6)

the chemical symbol for

osmium

British Dictionary definitions for OS (5 of 6)

abbreviation for

Old School
Old Style (method of reckoning dates)

Ordinary Seaman
(in Britain) Ordnance Survey
outsize
Old Saxon (language)

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

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 Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for Os

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