Lewis & Short

aspīrātĭo (adsp-), ōnis, f. [aspiro].

  1. I. In gen.
    1. A. Lit., a blowing or breathing to or upon: animantes adspiratione aëris sustinentur, by the blowing or breathing of the air (not by respiration, as it is commonly rendered), Cic. N. D. 2, 33, 83: ventorum, Lact. 7, 3 fin.
    2. B. Trop.: superni numinis, favor, Amm. 15, 2.
      Hence,
  2. II. Esp.
    1. A. Evaporation, exhalation: quae omnia fiunt et ex caeli varietate et ex disparili adspiratione terrarum, Cic. Div. 1, 36, 79; 1, 57, 130.
    2. B. In gram., the enunciation of a word with an h sound, a breathing, aspiration: ita majores locutos esse, ut nusquam nisi in vocali aspiratione uterentur, Cic. Or. 48, 160: per aspirationem apud nos potest quaeri, an in scripto sit vitium, si h littera est, non nota, Quint. 1, 5, 19; 1, 4, 9 Spald.; 1, 6, 21; 6, 3, 55 al.; cf. Apul. de Nota Aspirat. Osann.
      Hence meton., the aspirate, i.e. the letter H itself, Prisc. p. 547; 1038 al.; Phoc. Aspir. p. 1721 sq. P.