amphiboly

from WordNet (r) 3.0 (2006)

amphiboly
    n 1: an ambiguous grammatical construction; e.g., `they are
         flying planes' can mean either that someone is flying
         planes or that something is flying planes [syn:
         {amphibology}, {amphiboly}]

from The Collaborative International Dictionary of English v.0.48

Amphiboly \Am*phib"o*ly\, n.; pl. {Amphibolies}. [L. amphibolia,
   Gr. ?: cf. OE. amphibolie. See {Amphibolous}.]
   Ambiguous discourse; amphibology.
   [1913 Webster]

         If it oracle contrary to our interest or humor, we will
         create an amphiboly, a double meaning where there is
         none.                                    --Whitlock.
   [1913 Webster]