WordWeight : Weighing the Words

Pronunciation : Im"post
Part of Speech : n.
Etymology : [OF. impost, F. impot, LL. impostus, fr. L. impostus, p. p. of imponere to impose. See Impone.]
Definition : 1. That which is imposed or levied; a tax, tribute, or duty; especially, a duty or tax laid by goverment on goods imported into a country. Even the ship money . . . Johnson could not pronounce to have been an unconstitutional impost. Macaulay.

2. (Arch.)

Defn: The top member of a pillar, pier, wall, etc., upon which the weight of an arch rests.

Note: The impost is called continuous, if the moldings of the arch or architrave run down the jamb or pier without a break.

Syn. -- Tribute; excise; custom; duty; tax.
Source : Webster's Unabridged Dictionary, 1913