mescaline Syllabification: (mes·ca·line)Pronunciation: /ˈmeskəlin, -ˌlēn/Definition of mescaline noun a hallucinogenic and intoxicating compound present in mescal buttons from the peyote cactus. Alternative name: 3,4,5-trimethoxyphenethylamine; chemical formula: (CH3O)3C6H2CH2CH2NH2 mescaline in other Oxford dictionaries Definition of mescaline in the British & World English dictionary