don¹ / dän/ • n. 1. (Don) a Spanish title prefixed to a male forename. ∎  a Spanish gentleman; a Spaniard. ∎ inf. a high-ranking member of the Mafia.2. a university teacher, esp. a senior member of a college at Oxford or Cambridge.DERIVATIVES: don·ship / -ˌship/ n.don² • v. (donned , don·ning ) [tr.] put on (an item of clothing): in the locker room the players donned their football jerseys.

Don River of sw Russia. Rising se of Tula, it flows s, then sw to the Sea of Azov. Rostov is the major port. Annual floods are controlled by the Tsimlyansk Reservoir. The Don is navigable for 1370km (850mi), and is an important shipping route for grain, timber and coal. It is linked by canal to the River Volga. Length: 1930km (1200mi).

don 2, Don Sp. title prefixed to a man's Christian name; Sp. gentleman, Spaniard; distinguished or important man; (in English universities) head, fellow, or tutor of a college. XVII. — Sp. :- L. dominus (see DOM).

don 1 put on. XIV. contr. of do on; DO 1 (in the sense ‘put’) ON adv.

don a university teacher, especially a senior member of a college at Oxford or Cambridge; originally, a transferred colloquial use of the word as a Spanish title prefixed to a male forename.