ˌan(h)əˈlōnēəm- noun
Etymology: New Latin Anhalonium, genus of cacti, from Greek an- + halōnion small threshing floor (equated with New Latin areola areole, from Latin, small open space, diminutive of area piece of level ground, threshing floor), diminutive of halōn threshing floor; from the belief that the areoles were lacking — more at halo
: any of a group of alkaloids (as hordenine, mescaline) that are found in mescal buttons and that are used as cerebral stimulants and motor depressants — called also cactus alkaloid