The American Heritage® Dictionary of the English Language, 4th Edition
n. A poisonous alkaloid, C21H26N2O3, derived from the bark of a tree, Corynanthe yohimbe, and formerly used as an aphrodisiac, a local anesthetic, and a mydriatic.
n. A tryptamine alkaloid, the active chemical constituent of the medicinal herb Pausinystalia yohimbe: a stimulant and supposed aphrodisiac.
The Century Dictionary and Cyclopedia
n. A colorless dextrorotatory alkaloid, C23A32O4N2, found, together with yohimbenine, in the bark and leaves of the yohimbé or yumbehoa-tree, belonging to the Rubiaceæ. It crystallizes in needles and melts at 234° C.
Word Usage
"Yohimbe contains yohimbine, which is the alkaloid the FDA has allowed for treatment of erectile dysfunction."