Source : Webster's Revised Unabridged Dictionary (1913)

Trochus \Tro"chus\, n.; pl. {Trochi}. [NL., fr. Gr. ? a wheel.]
   (Zo["o]l.)
   Any one of numerous species of marine univalve shells
   belonging to {Trochus} and many allied genera of the family
   {Trochid[ae]}. Some of the species are called also
   {topshells}.