aa

noun16

1. •
   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.

   • We...saw ‘pahoihoi’ or solid lava forming, and also ‘aa’ or clinkers. — 1859
2. •
   Initialism of amino acid.
3. •
   Initialism of acetic acid.
4. •
   Initialism of atomic absorption.
5. •
   Initialism of ascending aorta.
6. •
   Initialism of author's alteration.
7. •
   Prescription notation: The stated amount of each of the substances is to be used in the compounding of the prescription
8. •
   Initialism of acting age.
9. •
   Initialism of arachidonic acid.
10. •
    Initialism of alveolar-arterial.
11. •
    Initialism of average audience.
12. •
    [plural only] Abbreviation of adjectives.
13. •
    [plural only] Abbreviation of arteries.
14. •
    Initialism of aminoacetone.
15. •
    Initialism of approximate absolute.
16. •
    Initialism of armature accelerator.

pronoun1

1. •
   I.

adjective3

1. •
   Abbreviation of ana (“of each, equal parts”).
2. •
   Initialism of arctic-alpine.
3. •
   Initialism of always afloat.

noun72

1. •
   An AA battery (energy-storage device).

   • Whether your camera takes AAs or a unique, proprietary battery, you should always have a spare. […] You will not be able to walk into a local supermarket and buy a new one as you can with AAs. — 2005
2. •
   A member of Alcoholics Anonymous.
3. •
   Initialism of anti-aircraft.

   • They're setting up an AA battery. That thing'll tear the Dawn apart... We'll wait for you to take the shot. — 2007
4. •
   Initialism of African-American.
5. •
   Initialism of Associate in Arts or Associate of Arts.

   • “I’m still figuring out my plans, but going back for another year is in my plans. I would be going back and getting my AA [degree], while playing another year of softball,” Enright said. — 2020
6. •
   Initialism of affirmative action.
7. •
   Initialism of amino acid.
8. •
   Initialism of Asian American.
9. •
   (US) Initialism of administrative assistant.
10. •
    Initialism of ascorbic acid.
11. •
    Initialism of antialiasing.
12. •
    Initialism of aortic aneurysm.
13. •
    Initialism of adoption agency.
14. •
    Initialism of aplastic anemia.
15. •
    Initialism of alopecia areata.
16. •
    Initialism of academic adviser.
17. •
    Initialism of athletic association.
18. •
    Initialism of Association Agreement: a treaty between the European Union, its member states and a non-EU country that creates a framework for cooperation between them.
19. •
    Abbreviation of all-around.
20. •
    Initialism of atomic absorption.
21. •
    Initialism of arachidonic acid.
22. •
    Initialism of acetic acid.
23. •
    Initialism of anesthesiologist assistant.
24. •
    Initialism of anesthesia assistant.
25. •
    Initialism of associate administrator.

    • I've worked at NASA as a graduate student working as a summer intern, and as an AA. Those are two of the most valuable experiences in my life. — 2011
26. •
    (UK) Initialism of appropriate adult.
27. •
    (UK) Initialism of annual allowance.
28. •
    Initialism of account aggregator.

    • The RBI had in 2016 approved a new class of NBFCs to act as account aggregators (AA). These AAs will play the role of providing services based on the explicit consent of individual clients. — 2019
29. •
    Initialism of arithmetic average.
30. •
    Initialism of allergic asthma.
31. •
    Initialism of acute appendicitis.
32. •
    Initialism of aortic arch.
33. •
    Initialism of ascending aorta.
34. •
    Initialism of abdominal aorta.
35. •
    Initialism of acrylic acid.
36. •
    Initialism of antiandrogen.
37. •
    Initialism of absolute alcohol.
38. •
    Initialism of assembly area.
39. •
    Initialism of air attaché.
40. •
    Initialism of average audience.
41. •
    Initialism of author's alteration.
42. •
    Initialism of anaplastic astrocytoma.
43. •
    Initialism of amyloid A.
44. •
    Initialism of antioxidant activity.
45. •
    Initialism of activated alumina.
46. •
    Initialism of adrenal androgen.
47. •
    Initialism of absolute altitude.
48. •
    Initialism of angular aperture.
49. •
    Initialism of airman apprentice.
50. •
    Initialism of appropriate authority.
51. •
    (Hong-Kong) Initialism of agent assistant; an assistant of a real estate agent.
52. •
    Initialism of appointed actuary.
53. •
    Initialism of Asian-African.
54. •
    Initialism of approach anxiety.
55. •
    Initialism of achievement age.
56. •
    Initialism of acting appointment.
57. •
    Initialism of avenue of approach.
58. •
    Initialism of assistant adjutant.
59. •
    Initialism of air armament.
60. •
    Initialism of aircraft apprentice.
61. •
    Initialism of aircraft artificer.
62. •
    Initialism of armament artificer.
63. •
    Initialism of aviation annex.
64. •
    Initialism of aminoacyl.
65. •
    Initialism of asymmetric aminohydroxylation.
66. •
    Initialism of acetaldehyde adduct.
67. •
    Initialism of anti-antibody.
68. •
    Initialism of anastomotic aneurysm.
69. •
    Initialism of arterial aneurysm.
70. •
    Initialism of arytenoid adduction.
71. •
    Initialism of approximate absolute.
72. •
    Initialism of against actual.

adjective6

1. •
   Initialism of anti-aircraft or anti-air.
2. •
   Initialism of Afro-Asiatic.
3. •
   Initialism of air-to-air.
4. •
   Initialism of Austroasiatic.
5. •
   Initialism of atlantoaxial.
6. •
   Initialism of arterioarterial.

verb1

1. •
   Initialism of antialias.

   • 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. — 1999