/ Dictionary / Index I interstate: Meaning and Definition of Find definitions for: in•ter•state Pronunciation: (adj.in"tur-stāt'n.in'tur&wdspcstāt"), [key] — adj. connecting or involving different states: interstate commerce. —n. a highway serving two or more states. (sometimes cap.) a highway that is part of the nationwide U.S. Interstate Highway System. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: interstate (Thesaurus) interstade Interstate Commerce Commission Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language