The Collaborative International Dictionary of English v.0.48:

Solarium \So*la"ri*um\, n.; pl. Solaria. [L. See Solar, n.]
   1. 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.
      [1913 Webster]

   2. (Zool.) 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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Perspective \Per*spec"tive\ (p[~e]r*sp[e^]k"t[i^]v), a. [L.
   perspicere, perspectum, to look through; per + spicere,
   specere, to look: cf. F. perspectif; or from E. perspective,
   n. See Spy, n.]
   1. Of or pertaining to the science of vision; optical. [Obs.]
      --Bacon.
      [1913 Webster]

   2. Pertaining to the art, or in accordance with the laws, of
      perspective.
      [1913 Webster]

   Perspective plane, the plane or surface on which the
      objects are delineated, or the picture drawn; the plane of
      projection; -- distinguished from the ground plane,
      which is that on which the objects are represented as
      standing. When this plane is oblique to the principal face
      of the object, the perspective is called oblique
      perspective; when parallel to that face, parallel
      perspective.

   Perspective shell (Zool.), any shell of the genus
      Solarium and allied genera. See Solarium.
      [1913 Webster]