(physics) The collective states of all electrons in an atom having the same principal quantum number (visualized as an orbit in which the electrons move).

(malacology) A marine univalve shell of the genus Bulla and certain shells of similar appearance of the now disused order Tectibranchiata of molluscs.

(zoology) A marine gastropod of the genus Crepidula. The species are numerous. / (zoology) A marine univalve shell of the genus Cymbium, syn. Cymba.

Alternative form of shellpad

Any of the marine gastropod mollusks of the genus Fasciolaria, especially Fasciolaria tulipa.

(malacology) Any of the family Arcidae of saltwater clams or marine bivalve molluscs.

A pad made or consisting of shells.

Any bivalve shell of the genus Mactra.

Any of various species of marine bivalve shells formerly belonging to the no longer accepted genus Avicula, now a synonym of Pteria, with species assigned to several genera, in which the hinge border projects like a wing.

(zoology) A brachiopod (Brachiopoda).