Any spiral marine shell of the genus Persona (now Distorsio), having a curiously twisted aperture.

One of the sessile cirripeds; a barnacle of the genus Balanus.

Alternative form of tortoiseshell

Alternative form of tortoiseshell

The shell of a tortoise, sometimes inaccurately the shell of a turtle, or that material. / Alternative form of tortoiseshell

Alternative form of hardshell

(physics, figuratively) Any half of a roughly spherical-like object; any dome-shaped object.

(rare, colloquial, especially with "on the") Inexpensive; not overpriced.

A method of casting metal used mainly for small pieces requiring relatively high accuracy.

(biology, of the embryo in an egg) That has partially developed but died without hatching.