"plant of the genus Agave," found in deserts of Mexico and southwestern U.S., especially the American aloe, or maguey plant, 1702, from Mexican Spanish, from Nahuatl (Aztecan) mexcalli "fermented drink made from agave," from metl "agave" + ixcalli "stew." Meaning "intoxicating liquor from fermented juice (pulque) of the agave" is attested in English from 1828. Also the name of a small desert cactus (peyote) found in northern Mexico and southern Texas (1885).
word-forming element in chemistry, often interchangeable with -in (2), though modern use distinguishes them; early 19c., from French -ine, the suffix commonly used to form words for derived substances, hence its extended use in chemistry. It was applied unsystematically at first (as in aniline), but now has more restricted use.
The French suffix is from Latin -ina, fem. form of -inus, suffix used to form adjectives from nouns, and thus is identical with -ine (1).
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Definitions of mescaline from WordNet
the hallucinatory alkaloid that is the active agent in mescal buttons;