the GNU version of the Collaborative International Dictionary of English
n. 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.
The Century Dictionary and Cyclopedia
n. A machine so constructed as to represent, by the movements of its parts, the motions and phases of the planets in their orbits. Similar machines are also called planetariums and cosmoscopes.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. planetarium consisting of an apparatus that illustrates the relative positions and motions of bodies in the solar system by rotation and revolution of balls moved by wheelwork; sometimes incorporated in a clock
Word Usage
"Other beginning words, such as orrery, posset and mornay, also defeated spellers."