RHYOLITE Meaning of RHYOLITE in English [ 'rʌɪəlʌɪt ]■ noun Geology a pale fine-grained volcanic rock of granitic composition.OriginC19: from Ger. Rhyolit , from Gk rhuax 'lava stream' + lithos 'stone'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004