I was going to the hole-in-the-wall to get some rhino the other day, when I started to wonder why cash is so-called.
I hit the books. Farmer & Henley gives no etymology. Partridge says
Origin problematic; there is probably some allusion to the size of a rhinoceros or the price which almost any part of its corpse will fetch as an aphrodisiac.
This is supported by the related terms rhino-fat, rhinoceral and rhinocerical, all meaning 'rich'.
ety. unk.; one suggestion, that it refers to the rhinoceros, then a fabulous creature 'worth its weight in gold', implies a certain lexicographical desperation
I had no luck with online sources either (here).
So, does anyone know why money is called rhino?