ἀραιόω

A. make porous, rarefy, τὴν ἐπιδερμίδα Hp. Nat.Puer. 20; τὴν σάρκα Id. Vict. 3.78; opp. πυκνόω, Arist. Pr. 884a27, Aret. CA 2.1, cf. SA 2.2, etc.

II. Pass., to be rarefied, Hp. Vict. 1.13, Arist. Mu. 394a36; ἀραιουμένων τῶν σωμάτων Ph. Bel. 71.43.