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(Astronomy) astronomy the period of revolution of a body about another with respect to one or more distant stars
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
The time taken for a planet to complete one orbit of the Sun.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited