/ Dictionary / Index P PKU: Meaning and Definition of Find definitions for: PKU Pronunciation: [key] phenylketonuria. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pku (Thesaurus) pkt. pkwy. Related Content Daily Word Quiz: miscreant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language