/ Dictionary / Index P phenylalanine: Meaning and Definition of Find definitions for: phen•yl•al•a•nine Pronunciation: (fen"l-al'u-nēn", -nin, fēn"-), [key] — n. Biochem. a crystalline, water-soluble, essential amino acid, CHCHCH(NH)COOH, necessary to the nutrition of humans and most animals, obtained chiefly from egg white or skim milk. Abbr.: Phe; Symbol: F&hasp; Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: phenylalanine (Thesaurus) phenylacetic acid phenylamine Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language