Definition of: impost

(im′pōst) noun
1. That which is imposed; specifically, a customs duty.
2. Archit. A projecting band or block placed at the top of a column or pier, and from which an arch springs. See illustration under ARCH.
3. Aweight carried by a horse in a handicap race. See synonyms under TAX.
—v.t. To classify so as to fix the customs duty: said of imported goods. [<OF <Med. L impostum <L impositus, pp. of imponere lay on <in- on + ponere lay, place]