/ Dictionary / Index I impost: Meaning and Definition of Find definitions for: im•post Pronunciation: (im'pōst), [key] — n. a tax; tribute; duty. a customs duty. the weight assigned to a horse in a race. —v.t. to determine customs duties on, according to the kind of imports. im•post Pronunciation: (im'pōst), [key] — n. Archit. the point of springing of an arch; spring. an architectural feature immediately beneath this point. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: impost (Thesaurus) impossible impost block Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language