libration Hear it!

libration definition

li·bra·tion (lī brās̸hən)

noun

  1. the act of librating
  2. Astron. a slight rocking motion of the moon which allows 59% of the moon's surface to be visible from the earth

Etymology: L libratio

Related Forms:

  • libratory li′·bra·to′ry (-brə tôr′ē) adjective

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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