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aa definition

☆ aa (ä′ä′)

noun

a type of basaltic rock, usually dark-colored with a jagged surface, formed in large sheets from slow-moving lava

Etymology: Haw ʼaʼā

AA definition

AA

  1. Alcoholics Anonymous
  2. antiaircraft
  3. Associate in (or of) Arts

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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