caffeine
/ˈkæfiːn/noun
mass noun
1- a crystalline compound which is found especially in tea and coffee plants and is a stimulant of the central nervous system咖啡因。
1.1
- An alkaloid, 1,3,7-trimethylxanthine; chem. formula: C8H10N4O2.生物碱, 1,3, 7-三甲黄嘌呤; 化学分子式：C8H10N4O2.
词源
mid 19th cent.: from French caféine, from café 'coffee'.