ˈwent ə lˌtrap noun
Etymology: Dutch wenteltrap winding stair, from Middle Dutch wendeltrappe, from wendel turning, winding (from wenden to turn) + trappe step, stairs; akin to Old English wendan to turn, wend — more at wend , trap
1. : any of numerous graceful usually white spirally coiled and tapering gastropod mollusk shells that have longitudinal ridges surrounding the whorls, are favorites with collectors, and include one form formerly commanding very high prices — called also staircase shell
2. : any of various mollusks (family Epitoniidae) of which the shell is a wentletrap