- a great circle on the celestial sphere passing through the zenith.
Origin of vertical circle
First recorded in 1550–60
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- astronomy a great circle on the celestial sphere passing through the zenith and perpendicular to the horizon
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- A great circle on the celestial sphere that passes through the zenith and the nadir and thus is perpendicular to the horizon.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.