os

1 of 4

noun (1)

ˈäs 

plural ossa ˈä-sə 

: bone

os

2 of 4

noun (2)

ˈōs 

plural ora ˈȯr-ə 

: orifice

Os

3 of 4

symbol

osmium

OS

4 of 4

abbreviation

1

[Latin oculus sinister] left eye

2

Old Style

3

operating system

4

out of stock

Word History

Etymology

Noun (1)

Latin oss-, os — more at osseous

Noun (2)

Latin or-, os — more at oral

First Known Use

Noun (1)

15th century, in the meaning defined above

Noun (2)

1737, in the meaning defined above

Medical Definition

os

1 of 4 noun

ˈäs 

plural ossa ˈäs-ə 

: bone see os calcis, os coxae

os

2 of 4 noun

ˈōs 

plural ora ˈōr-ə, ˈȯr-ə 

: orifice see external os, internal os, per os

Os

3 of 4 symbol

osmium

OS

4 of 4 abbreviation

left eye

—used in writing prescriptions

Etymology

Abbreviation

Latin oculus sinister