O/S

(of the calendar) Old Style.

* * *

os¹ «os», noun, plural os|sa «OS uh».

Latin. a bone.

os² «os», noun, plural o|ra «AWR uh, OHR-».

Latin. a mouth; opening.

os³ «ohs», noun, plural o|sar.

Geology. an esker.

╂[< Swedish ås ridge (of a hill or roof); åsar, plural]

os-,

prex, the form of ob- (Cf. ↑ob-) in some cases before c and t, as in oscine, ostensible.

o.s. or o/s (no periods),

out of stock.

Os (no periods),

osmium (chemical element).

OS (no periods) or O.S.

Old Saxon.

O.S.,

1. Old Style,

2. ordinary seaman.