aa

1. (aviation) Initialism of American Airlines: a major American airline headquartered in Fort Worth, Texas.Examples: "Alas, I fear, Netflix will soon break my heart. And it's an American icon that is warning me: American Airlines (AA). ¶ You see, middlemen are dying. Sabre, the former AA subsidiary that is now an independent global distribution system (GDS) supplying travel agencies and online travel agencies with ticket and pricing information, recently announced it was raising the rates it charges on AA tickets."abbreviationalt-ofinitialism

2. (aviation) Initialism of Aerolíneas Argentinas.abbreviationalt-ofinitialism

3. (aviation) Initialism of Ansett Australia or Ansett Airways.abbreviationalt-ofinitialism

4. (US, baseball) Double-A: the second-highest level of play in Minor League Baseball after Triple-A (AAA).US

5. (US, historical, baseball) Initialism of American Association: an American minor league baseball league from 1902 to 1962 and 1969 to 1997.USabbreviationalt-ofhistoricalinitialism

6. (UK, automotive) Initialism of The Automobile Association: a British motoring association founded in 1905.Examples: "As we have said before, never accept an AA increase – if you phone up and threaten to leave they will, in our experience, drop it back to the previous price. Or better still, just keep switching provider each year. LV’s cover is a good alternative."UKabbreviationalt-ofinitialism

1. (military, aviation) Initialism of anti-aircraft or anti-air.abbreviationalt-ofinitialismnot-comparable

2. (military, aviation) Initialism of air-to-air.abbreviationalt-ofinitialismnot-comparable

3. (anatomy, medicine) Initialism of atlantoaxial.Examples: "AA joint; AA instability"abbreviationalt-ofinitialismnot-comparable

4. (anatomy, medicine) Initialism of arterioarterial.Examples: "AA anastomosis"abbreviationalt-ofinitialismnot-comparable

5. (linguistics) Initialism of Afro-Asiatic.abbreviationalt-ofinitialismnot-comparable

6. (linguistics) Initialism of Austroasiatic.abbreviationalt-ofinitialismnot-comparable

1. (computer graphics, transitive) Initialism of antialias.Examples: "On the other hand, edge AA in EF2000 didn't make much difference because only the objects were AAed and they made up only a very small percentage of the screen area."; "Vector images can be considered to have extremely high resolution, so it is possible to AA them."abbreviationalt-ofinitialismtransitive

1. (volcanology) A form of lava flow associated with Hawaiian-type volcanoes, consisting of basaltic rock, usually dark-colored with a jagged and loose, clinkery surface. Compare pahoehoe.Examples: "We...saw ‘pahoihoi’ or solid lava forming, and also ‘aa’ or clinkers."; "Cooling and solidification frequently takes a different course [...] in lava flows, producing the clinker-like ‘aa’ lava."; "Both pahoehoe and aa lava flows are common on the upper slopes of Mauna Loa with a preponderance of aa flows found at the lower elevations."uncountable

1. (medicine) Initialism of alveolar-arterial.abbreviationalt-ofinitialism