Wiktionary
n. (context organic compound English) A nitrogenous bicyclic heterocycle, mainly known for a group of alkaloids derived from it, including atropine and cocaine.
Wikipedia
Tropane is a nitrogenous [3.2.1] bicyclic organic compound. It is mainly known for a group of alkaloids derived from it (called tropane alkaloids), which include, among others, atropine and cocaine. Tropane alkaloids occur in plants of the families Erythroxylaceae (including coca) and Solanaceae (including mandrake, henbane, deadly nightshade, datura, potato, tomato).
The nitrogen bridge is between C-1 and C-5; there are two asymmetric carbons, but tropane is optically inactive due to symmetry.
8-Azabicyclo[3.2.1]octane (tropane without the N- methyl group) is known as nortropane or nor-tropane.