caf·feine also caf·fein (kă-fēn, kăfēn′)
A bitter white alkaloid, C8H10N4O2, found in certain plants such as cacao, coffee, kola, and tea, that stimulates the central nervous system and body metabolism and is used in medicine, usually in combination with other drugs, to relieve headaches and treat respiratory conditions in premature infants.
[German Kaffein (from Kaffee, coffee) or French caféine, both from French café, coffee; see CAFé.]
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