Breadcrumb Home > Dictionary > Index A asteroid: Meaning and Definition of Find definitions for: as•ter•oid Pronunciation: (as'tu-roid"), [key] — n. Also calledany of the thousands of small bodies of from 480 miles (775 km) to less than one mile (1.6 km) in diameter that revolve about the sun in orbits lying mostly between those of Mars and Jupiter. an asteroidean; a starfish. —adj. starlike. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: asteroid (Thesaurus) asternal asteroid belt ✖ Related Content Daily Word Quiz: umbrage Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language