- rarefy (v.)
[rarefy 词源字典]
- late 14c., from Old French rarefier (14c.) and directly from Medieval Latin rarificare, from Latin rarefacere "make rare," from rarus "rare, thin" (see rare (adj.1)) + facere "to make" (see factitious). Related: Rarefied.[rarefy etymology, rarefy origin, 英语词源]