Ps Definition

abbreviation
Picosecond.
American Heritage
Police sergeant.
American Heritage
Postscript.
Webster's New World
Psalm(s)
Webster's New World
Passenger steamer.
Webster's New World
symbol

(physics) Positronium.

Wiktionary

(metrology) Symbol for the petasecond, an SI unit of time equal to 1015 seconds.

Wiktionary