/kwuy"nuyn, kwin"uyn/ or, esp. Brit., /kwi neen"/ , n. Chem., Pharm.
1. a white, bitter, slightly water-soluble alkaloid, C 20 H 24 N 2 O 2 , having needlelike crystals, obtained from cinchona bark: used in medicine chiefly in the treatment of resistant forms of malaria.
2. a salt of this alkaloid, esp. the sulfate.
[ 1820-30; quin ( a ) ( kina bark) + -INE 2 ]