/ Dictionary / Index A actinoid: Meaning and Definition of Find definitions for: ac•ti•noid Pronunciation: (ak'tu-noid"), [key] — adj. raylike; radiate. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: actinoid (Thesaurus) actinograph actinolite Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language