D defs.my
Entry 1 sense Webster, 1913

Orrery

/ôr'-ẽr-ē/ · Or·re·ry · IPA /ˈɔɹ.ə.ɹi/
01 n. An apparatus which illustrates, by the revolution of balls moved by wheelwork, the relative size, periodic motions, positions, orbits, etc.…
pl. Orreries ((#))
  1. 1.
    An apparatus which illustrates, by the revolution of balls moved by wheelwork, the relative size, periodic motions, positions, orbits, etc., of bodies in the solar system.