1Capable of taking various courses of action; adaptable, versatile.
Frequently as an epithet of Odysseus (with allusion to Homer's Odyssey).
2Of a bee or other insect: visiting the flowers of many species.
Relating to or characterized by the constraint that pressure and volume vary in such a way that a specific heat remains constant, or (more widely) by the constraint that pressure, temperature, entropy, and volume vary in such a way that a particular property remains constant. Also (rarely) as noun: a graph showing such a variation.
Of or relating to a star modelled as a sphere in hydrostatic equilibrium such that at a given radial distance the pressure P and density ρ are related by P = K ρ(n + 1)/ n, where K is a constant.
Mid 19th century; earliest use found in Fraser's Magazine for Town and Country. From ancient Greek πολύτροπος turning many ways, versatile, etc., (also) much-travelled (epithet of Odysseus in Homer's Odyssey (goes to post-classical Latin polytropus); from πολυ- + -τροπος see -trope) + -ic.