The Collaborative International Dictionary of English v.0.48:

Geometry \Ge*om"e*try\, n.; pl. Geometries[F. g['e]om['e]trie,
   L. geometria, fr. Gr. ?, fr. ? to measure land; ge`a, gh^,
   the earth + ? to measure. So called because one of its
   earliest and most important applications was to the
   measurement of the earth's surface. See Geometer.]
   1. That branch of mathematics which investigates the
      relations, properties, and measurement of solids,
      surfaces, lines, and angles; the science which treats of
      the properties and relations of magnitudes; the science of
      the relations of space.
      [1913 Webster]

   2. A treatise on this science.
      [1913 Webster]

   Analytical geometry, or Co["o]rdinate geometry, that
      branch of mathematical analysis which has for its object
      the analytical investigation of the relations and
      properties of geometrical magnitudes.

   Descriptive geometry, that part of geometry which treats of
      the graphic solution of all problems involving three
      dimensions.

   Elementary geometry, that part of geometry which treats of
      the simple properties of straight lines, circles, plane
      surface, solids bounded by plane surfaces, the sphere, the
      cylinder, and the right cone.

   Higher geometry, that pert of geometry which treats of
      those properties of straight lines, circles, etc., which
      are less simple in their relations, and of curves and
      surfaces of the second and higher degrees.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Descriptive \De*scrip"tive\, a. [L. descriptivus: cf. F.
   descriptif.]
   Tending to describe; having the quality of representing;
   containing description; as, a descriptive figure; a
   descriptive phrase; a descriptive narration; a story
   descriptive of the age.
   [1913 Webster]

   Descriptive anatomy, that part of anatomy which treats of
      the forms and relations of parts, but not of their
      textures.

   Descriptive geometry, that branch of geometry. which treats
      of the graphic solution of problems involving three
      dimensions, by means of projections upon auxiliary planes.
      --Davies & Peck (Math. Dict. ) -- De*scrip"tive*ly, adv.
      -- De*scrip"tive*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

descriptive geometry
    n 1: the geometry of properties that remain invariant under
         projection [syn: projective geometry, descriptive
         geometry]