/ Dictionary / Index A astroid: Meaning and Definition of Find definitions for: as•troid Pronunciation: (as'troid), [key] — n. Geom. a hypocycloid with four cusps. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. astrograph astro-inertial guidance Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language