"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).
"agave plant, the American aloe," 1550s, from Spanish, from Taino (Arawakan), a native Haitian language.
fermented drink in Mexico and parts of Central America made from the juice of the agave, 1690s, from American Spanish pulque, a word of unknown origin, said to be a word from Araucanian (native language spoken in part of Chile), or else from some language of Mexico.
A secondary sense is older in English: "Fragrant resin or heartwood of an East Indian tree" (Old English alewe, aloe), which is from misuse of Latin/Greek aloe in Biblical translations for Hebrew akhalim (plural), which ultimately is perhaps from a Dravidian language. OED says the Greek word probably was chosen for sound-resemblance to the Hebrew one.
The word was then misapplied in 1680s to the American agave plant, which is similar but unrelated. The "true aloe" (producing the drug) consequently is called aloe vera (with Latin vera "true;" see very). Related: Aloetic.