ora

o·ra

 (ôr′ə)

n.

Plural of os¹.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

ora

(ˈɔːrə)

n

(Anatomy) the plural of os²

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

os¹

(ɒs)

n., pl. os•sa (ˈɒs ə)

a bone.

[1540–50; < Latin]

os²

(ɒs)

n., pl. o•ra (ˈɔr ə, ˈoʊr ə)

a mouth or orifice of the body.

[1730–40; < Latin ōs mouth]

OS

1. Old Saxon.

2. Computers. operating system.

Os

Chem. Symbol.

osmium.

O.S.

1. (in prescriptions) the left eye.

[< Latin oculus sinister]

2. old series.

3. ordinary seaman.

Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.