O.S.

1

or o.s.

Origin of O.S.

1
From the Latin word oculus sinister

O.S.

2
  1. Old Saxon.
  2. Old School.
  3. Old series.
  4. (of the calendar) Old Style.
  5. Also o.s. ordinary seaman.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for o.s.

o.s.

OS or 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