Definition of solarium

• n. - An apartment freely exposed to the sun; anciently, an apartment or inclosure on the roof of a house; in modern times, an apartment in a hospital, used as a resort for convalescents.
• n. - Any one of several species of handsome marine spiral shells of the genus Solarium and allied genera. The shell is conical, and usually has a large, deep umbilicus exposing the upper whorls. Called also perspective shell.