Source : Webster's Revised Unabridged Dictionary (1913)

Telson \Tel"son\, n.; pl. {Telsons}. [NL., fr. Gr. ? a boundary,
   limit.] (Zo["o]l.)
   The terminal joint or movable piece at the end of the abdomen
   of Crustacea and other articulates. See {Thoracostraca}.