資料來源 : Webster's Revised Unabridged Dictionary (1913)

Hyperboloid \Hy*per"bo*loid\, n. [Hyperbola + -oid: cf. F.
   hyperbolo["i]de.] (Geom.)
   A surface of the second order, which is cut by certain planes
   in hyperbolas; also, the solid, bounded in part by such a
   surface.

   {Hyperboloid of revolution}, an hyperboloid described by an
      hyperbola revolving about one of its axes. The surface has
      two separate sheets when the axis of revolution is the
      transverse axis, but only one when the axis of revolution
      is the conjugate axis of the hyperbola.