O. S.
See also:
Appendix:Variations of "os"
English
Noun
O.
S.
(
uncountable
)
Alternative form of
OS
.
(
calendar systems
)
Abbreviation of
old style
.
Anagrams
SO
,
S/O
,
s.o.
,
so
,
So
,
So.
,
S&O
,
s/o
,
S.O.