Impost- that which is imposed or levied; a tax, tribute, or duty; a charge usually of money collected by the government from people or businesses; a customs-duty; the basic curve for the definition of the dome, generated through the section of a horizontal plane with the ceiling; a block, capital, or molding from which an arch springs; the point where an arch rests on a wall or column; a block, capital, or molding from which an arch springs; the condition of such resting or meeting; a weight placed upon a horse in a handicap race.