os

1
[ os ]
/ ɒs /

noun, plural os·sa [os-uh] /ˈɒs ə/.

Anatomy, Zoology. a bone.

Origin of os

1
Borrowed into English from Latin around 1540–50

Definition for os (2 of 11)

os

2
[ 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

2
First recorded in 1730–40, os is from the Latin word ōs mouth

Definition for os (3 of 11)

os

3
[ ohs ]
/ oʊs /

noun, plural o·sar [oh-sahr] /ˈoʊ sɑr/.

Geology. an esker, especially when of great length.

Origin of os

3
< Swedish ås (plural åsar) ridge

Definition for os (4 of 11)

Os


Symbol, Chemistry. osmium.

Definition for os (5 of 11)

OS


Old Saxon.
Computers. operating system.

Definition for os (6 of 11)

O, o

[ oh ]
/ oʊ /

noun, plural O's or Os; o's or os or oes.

the fifteenth letter of the English alphabet, a vowel.
any spoken sound represented by the letter O or o, as in box, note, short, or love.
something having the shape of an O.
a written or printed representation of the letter O or o.
a device, as a printer's type, for reproducing the letter O or o.

Definition for os (7 of 11)

O

[ oh ]
/ oʊ /

interjection

(used before a name in direct address, especially in solemn or poetic language, to lend earnestness to an appeal): Hear, O Israel!
(used as an expression of surprise, pain, annoyance, longing, gladness, etc.)

noun, plural O's.

the exclamation “O.”

Origin of O

1125–75; Middle English < Old French < Latin ō

Can be confused

O oh owe

Definition for os (8 of 11)

o/s


(of the calendar) Old Style.
out of stock.
(in banking) outstanding.

Definition for os (9 of 11)

O/S


(of the calendar) Old Style.

Definition for os (10 of 11)

O.S.

1

or o.s.


(in prescriptions) the left eye.

Origin of O.S.

1
From the Latin word oculus sinister

Definition for os (11 of 11)

O.S.

2

Old Saxon.
Old School.
Old series.
(of the calendar) Old Style.
Also o.s. ordinary seaman.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for os

British Dictionary definitions for os (1 of 9)

os

1
/ (ɒs) /

noun plural ossa (ˈɒsə)

anatomy the technical name for bone

Word Origin for os

C16: from Latin: bone; compare Greek osteon

British Dictionary definitions for os (2 of 9)

os

2
/ (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 9)

os

3
/ (əʊs) /

noun plural osar (ˈəʊsɑː)

another name for esker

Word Origin for os

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

British Dictionary definitions for os (4 of 9)

Os


the chemical symbol for

osmium

British Dictionary definitions for os (5 of 9)

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 9)

o

O

/ (əʊ) /

noun plural o's, O's or Os

the 15th letter and fourth vowel of the modern English alphabet
any of several speech sounds represented by this letter, in English as in code, pot, cow, move, or form
another name for nought

British Dictionary definitions for os (7 of 9)

o.s.

OS or O/S


abbreviation for

out of stock
banking outstanding

British Dictionary definitions for os (8 of 9)

O

1

symbol for

chem oxygen
a human blood type of the ABO groupSee universal donor
logic a particular negative categorial proposition, such as some men are not married: often symbolized as SoPCompare A, E, I 2

abbreviation for

Australian slang offence

Word Origin for O

(for sense 3) from Latin (neg) o I deny

British Dictionary definitions for os (9 of 9)

O

2
/ (əʊ) /

interjection

a variant spelling of oh
an exclamation introducing an invocation, entreaty, wish, etcO God!; O for the wings of a dove!
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

Medicine definitions for os (1 of 2)

Os


The symbol for the elementosmium

Medicine definitions for os (2 of 2)

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.

Science definitions for os (1 of 3)

Os


The symbol for osmium.

Science definitions for os (2 of 3)

O


The symbol for oxygen.

Science definitions for os (3 of 3)

osmium

[ ŏzmē-əm ]

Os

A hard, brittle, bluish-white metallic element that is the densest naturally occurring element. It is used to make very hard alloys for fountain pen points, electrical contacts, and instrument pivots. Atomic number 76; atomic weight 190.2; melting point 3,000°C; boiling point 5,000°C; specific gravity 22.57; valence 2, 3, 4, 8. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.