Button shell

(Zool.) a small, univalve marine shell of the genus Rotella.

See also: Button

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
The ideal button shell was oval-shaped, uniformly thick, and sported an outer surface free of bumps or knobs.
Tear gas, rubber bullets, plastic pellets, stun grenade, multi button shells were the other non lethal weapons that were pressed into action for dispersing the violent crowds.
"If I start out by selling 100 buttons," I reasoned, "then I need 100 button shells, a pack of paper, and a circle cutter, which totals about $40."