The Collaborative International Dictionary of English v.0.48:

Zeugma \Zeug"ma\, n. [L., from Gr. ?, fr. ? to yoke, join. See
   Yoke.] (Gram.)
   A figure by which an adjective or verb, which agrees with a
   nearer word, is, by way of supplement, referred also to
   another more remote; as, "hic illius arma, hic currus fuit;"
   where fuit, which agrees directly with currus, is referred
   also to arma.
   [1913 Webster]

WordNet (r) 3.0 (2006):

zeugma
    n 1: use of a word to govern two or more words though
         appropriate to only one; "`Mr. Pickwick took his hat and
         his leave' is an example of zeugma"