tropism UK /ˈtɹəʊpɪz(ə)m/US /ˈtɹoʊˌpɪzəm/ noun3 •The turning of an organism (chiefly a plant) or part of an organism either towards or away from a stimulus; (countable) an instance of this. •(figurative) Of a person: an instinctive predilection or tendency; also (generally), a liking, a preference. •A capability or tendency for a pathogen (chiefly a virus) to infect a type of cell, tissue, organ, or host organism.HBLV [human B-cell lymphotropic virus] has a broad range of cell tropisms, and it infects B cells, T cells, megakaryocytes, and glioblastoma cells. — 1989 formstropisms