impost (n.) Look up impost at
"tax, duty," 1560s, from Middle French impost (15c., Modern French impôt), from Medieval Latin impostum "a tax imposed," noun use of neuter of Latin impostus, contracted form of impositus, past participle of imponere "to place upon, impose upon" (see impostor). Compare depot. As an architectural term, 1660s, from French imposte (16c.), from Italian imposta, from the same Latin source.