jēˈä.trəˌpizəm noun
Etymology: International Scientific Vocabulary ge- + -tropism; originally formed as German geotropismus
1. : tropism in which gravitational attraction is the orienting factor (as in roots growing down, shoots growing up, and the climbing, swimming, or right-side-up orientation of certain animals)
2. : tropism in which turning or movement is toward rather than away from the earth — compare apogeotropism