TROPISM Meaning of TROPISM in English [ 'trəʊpɪz(ə)m , 'trɒp- ]■ noun Biology the turning of all or part of an organism in response to an external stimulus.OriginC19: from Gk tropos 'turning' + -ism . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004