evening star or morning star, planet that becomes visible in the western sky shortly after sunset or in the eastern sky shortly before sunrise. It can usually be seen in twilight, when it is too light for the true stars to be seen. Venus and Mercury are often seen as evening or morning stars. Other planets, especially Mars and Jupiter, may appear as evening or morning stars at certain points in their orbits.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.