ἀραίωσις
εως, ἡ
A.
becoming or making porous, rarefaction, opp. πύκνωσις, dub. in Epicur. Nat. 14 Fr. 11 (cf. Fr. 6), cf. Plu. Strom. 3, D.L. 9.8 (Heraclit.), Corn. ND 17, etc.
2.
Medic., porosity, of the lungs, Hp. Oss. 13, etc.
3.
mordanting, PHolm. 8.3.