Definition of "moonquake" [moonquake]

• A quake or series of vibrations on the moon similar to an earthquake but usually of very low magnitude. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The impact caused a minor "moonquake" that scientists used to learn about the moon's interior structure."
• "After 30 seconds, the computer shut down the generator. “Damn, ” announced Murphy, “I didn†™ t expect there to be a moonquake."
• "FLATOW: The Apollo astronauts also left, on the surface, if I remember correctly, some earthquake, moonquake detectors."