The Collaborative International Dictionary of English v.0.48:

Aspirate \As"pi*rate\, v. t. [imp. & p. p. Aspirated; p. pr. &
   vb. n. Aspirating.] [L. aspiratus, p. p. of aspirare to
   breathe toward or upon, to add the breathing h; ad + spirare
   to breathe, blow. Cf. Aspire.]
   To pronounce with a breathing, an aspirate, or an h sound;
   as, we aspirate the words horse and house; to aspirate a
   vowel or a liquid consonant.
   [1913 Webster]