/ Dictionary / Index P PTO: Meaning and Definition of Find definitions for: PTO Pronunciation: [key] Patent and Trademark Office. See P.T.O. Pronunciation: [key] please turn over (a page or leaf&hasp;). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pto (Thesaurus) PTM Ptolemaeus Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language