pentaconter

from The Collaborative International Dictionary of English v.0.48

Pentaconter \Pen"ta*con`ter\, n. (Gr. Antiq.)
   See {Penteconter}.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Penteconter \Pen"te*con`ter\, n. [Gr. ? (sc. ?), fr. ? fifty.]
   (Gr. Antiq.)
   A Grecian vessel with fifty oars. [Written also
   {pentaconter}.]
   [1913 Webster]