The Collaborative International Dictionary of English v.0.48:

Proclitic \Pro*clit"ic\, a. [Gr. ? to lean forward; ? forward +
   ? to lean or incline. Cf. Enclitic.] (Gr. Gram.)
   Leaning forward; -- said of certain monosyllabic words which
   are so closely attached to the following word as not to have
   a separate accent.
   [1913 Webster]