/ Dictionary / Index U undulatory theory: Meaning and Definition of Find definitions for: un'dulatory the"ory Pronunciation: [key] — Physics. Physics. See(def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. undulatory undulatus Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language