The Collaborative International Dictionary of English v.0.48:

Cavity \Cav"i*ty\, n.; pl. Cavities. [L. cavus hollow: cf. F.
   cavit['e].]
   1. Hollowness. [Obs.]
      [1913 Webster]

            The cavity or hollowness of the place. --Goodwin.
      [1913 Webster]

   2. A hollow place; a hollow; as, the abdominal cavity.
      [1913 Webster]

            An instrument with a small cavity, like a small
            spoon.                                --Arbuthnot.
      [1913 Webster]

            Abnormal spaces or excavations are frequently formed
            in the lungs, which are designated cavities or
            vomic[ae].                            --Quain.
      [1913 Webster]

   Body cavity, the c[oe]lum. See under Body.
      [1913 Webster]