the small component of the precession of the equinoxes contributed by the motion of the ecliptic, the change in orientation of the plane of the earth’s orbit being produced by the gravitational attraction of the planets.
[plan-i-tes-uh-muh l] /ˌplæn ɪˈtɛs ə məl/ Astronomy noun 1. one of the small celestial bodies that, according to one theory (planetesimal hypothesis) were fused together to form the of the solar system. adjective 2. of or relating to a planetesimal or planetesimals. planetesimal (plān’ĭ-těs’ə-məl) Any of innumerable small bodies of accreted gas and dust thought […]
noun, Machinery. 1. any of the gears in an epicyclic train surrounding and engaging with the sun gear.
[plan-i-tol-uh-jee] /ˌplæn ɪˈtɒl ə dʒi/ noun 1. the branch of astronomy that deals with the physical features of the . /ˌplænɪˈtɒlədʒɪ/ noun 1. (astronomy) the study of the origin, composition, and distribution of matter in the planets
[plan-i-toid] /ˈplæn ɪˌtɔɪd/ noun, Astronomy. 1. an asteroid. /ˈplænɪˌtɔɪd/ noun 1. another name for asteroid (sense 1) planetoid (plān’ĭ-toid’) See asteroid.