Source : Webster's Revised Unabridged Dictionary (1913)

Coussinet \Cous"si*net`\ (k??s"s?-n?t`), n. [F., dim. of coussin
   cushion. See {Cushionet}.] (Arch.)
   (a) A stone placed on the impost of a pier for receiving the
       first stone of an arch.
   (b) That part of the Ionic capital between the abacus and
       quarter round, which forms the volute. --Gwilt.