WordReference Random House Unabridged Dictionary of American English © 2019
a•a  ä),USA pronunciation n. 
  1. Geology, Drugsbasaltic lava having a rough surface.
Also,  a'a. Cf.  pahoehoe. 
  • Hawaiian ‘a‘ā
  • 1855–60

  1. ClothingSee  administrative assistant. 
  2. Clothing, See  Alcoholics Anonymous. 
  3. Business, Militaryantiaircraft.
  4. See  author's alteration. 

AA,  Symbol.
  1. a proportional shoe width size, narrower than A and wider than AAA.
  2. the smallest proportional brassiere cup size.
  3. a quality rating for a corporate or municipal bond, lower than AAA and higher than A.
  4. [Elect.]a battery size for 1.5 volt dry cells: diameter, 0.6 in. (1.4 cm);
    length, 2 in. (5 cm).
  5. British Termsa designation for motion pictures certified as unsuitable for children under 14 unless accompanied by an adult. Cf. A (def. 11), U (def. 5), X (def. 9).

  1. (in prescriptions) ana2.
Also,  āa 
  • Greek aná, with superscript bar representing the nasal consonant

  1. See  Alcoholics Anonymous. 
  2. Militaryantiaircraft.
  3. Militaryantiaircraft artillery.
  4. Associate in Accounting.
  5. See  Associate of Arts. 
  6. See  author's alteration. 

  • See  author's alteration. 
  • Also,  aa 
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