The Collaborative International Dictionary
Telsons
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.
Wiktionary
telsons
n. (plural of telson English)