/ Dictionary / Index P PST: Meaning and Definition of Find definitions for: PST Pronunciation: [key] Pacific Standard Time. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pst (Thesaurus) psst psych Related Content Daily Word Quiz: lyceum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language