Source : Webster's Revised Unabridged Dictionary (1913)

Jettison \Jet"ti*son\ n. [See {Jetsam}.]
   1. (Mar. Law) The throwing overboard of goods from necessity,
      in order to lighten a vessel in danger of wreck.

   2. See {Jetsam}, 1.

Source : WordNet®

jettison
     v 1: throw away, of something encumbering
     2: throw as from an airplane