Jump To:

• aa
  aa

  noun

  basaltic lava having a rough surface.
• AA
  AA

  abbreviation

  administrative assistant.
• a̅a̅
  a̅a̅

  (in prescriptions) ana.
• a.a.
  a.a.

  abbreviation

  author's alteration. Also A.A., AA
• A.A.
  A.A.

  abbreviation

  Alcoholics Anonymous.

aa

¹ American  

[ah-ah] / ˈɑ ɑ /

Or a'a,

noun

1. basaltic lava having a rough surface.

---

AA ² American  

abbreviation

1. administrative assistant.

---

AA ³ American  

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. Electricity. a battery size for 1.5-volt dry cells: diameter, 0.6 inch (1.4 centimeters); length, 2 inches (5 centimeters).

5. British. a designation for motion pictures certified as unsuitable for children under 14 unless accompanied by an adult.

---

a̅a̅ ⁴ American  

Or āa

Symbol.

1. (in prescriptions) ana.

---

a.a. ⁵ American  

Or aa

abbreviation

1. author's alteration. Also A.A., AA

---

A.A. ⁶ American  

[ay-ay] / ˈeɪˈeɪ /

Or AA

abbreviation

1. Alcoholics Anonymous.

---

A.A. ⁷ American  

abbreviation

1. antiaircraft. Also AA

2. Associate in Accounting.

3. Associate of Arts.

---

AA ¹ British  

abbreviation

1. Alcoholics Anonymous

2. anti-aircraft

3. Architectural Association

4. (in Britain) Automobile Association

5. (in Britain) Advertising Association

---

symbol

1. (in Britain, formerly) a film that may not be shown publicly to a child under fourteen

aa ² British  

/ ˈɑːɑː /

noun

1. a volcanic rock consisting of angular blocks of lava with a very rough surface

---

aa ³ British  

abbreviation

1. ana ¹

---

aa Scientific  

/ ä′ä /

1. A type of lava having a rough, jagged surface. It is relatively slow moving in its molten state, advancing in the form of massive blocks with fissured and angular surfaces that ride on a viscous interior. The blocks range in size between the size of a football and the size of a house.

2. See Note at pahoehoe

---

Etymology

Origin of aa¹

First recorded in 1855–60; from Hawaiian ʿaʿā

Origin of a̅a̅⁴

From the Greek word aná, with superscript bar representing the nasal consonant

Example Sentences

See Examples For:

aa AA A.A.

Mr. Warsh is known as aa inflation hawk, which makes Mr. Trump’s nomination especially notable.

From The Wall Street Journal ● Jan. 30, 2026

The analysis revealed that in many cases, changes in the environment, such as steepening slopes or increasing eruption rates, amplified the ripples, which could lead to runaway mixing—and the likely formation of aa.

From Science Magazine ● Jun. 9, 2023

Peterson, D. W. & Tilling, R. I. Transition of basaltic lava from pahoehoe to aa, Kilauea Volcano, Hawaii: Field observations and key factors - ScienceDirect.

From Textbooks ● Jan. 1, 2017

"Ranjish hee sahi," says one Facebook update, "dil hee dukhaane ke liye aa!"

From The Guardian ● Jun. 14, 2012

"What in aa conscience is the meanin' o' this?"

From Two Knapsacks A Novel of Canadian Summer Life by John Campbell

The AA said its campaigning had persuaded the UK government to set up pump-price transparency.

From BBC ● Sep. 25, 2026

He brought it to the American baggage services office and called after tracking me down, probably by the AA frequent flier number on my new AA credit card I pulled out on the plane.

From The Wall Street Journal ● Sep. 18, 2026

In March, the CMA ordered the owner of the AA and BSM driving schools to pay refunds to more than 80,000 learners after failing to disclose the total price for lessons upfront during booking online.

From BBC ● Jun. 23, 2026

The AA recorded 5,241 pothole-related incidents in Scotland in March, an increase of almost 8% on the previous month.

From BBC ● May 14, 2026

AA 23:234: “For one quarter, Black Tiger lets me escape from my rotten existence for three glorious hours. Pretty good deal.”

From "Ready Player One: A Novel" by Ernest Cline

“Emancipation Day was usually the occasion of the beating of drums and the marching of militia,” wrote A.A.

From Salon ● Jun. 19, 2026

Another fun fact: The New York Public Library has the original stuffed animals that belonged to A.A.

From The Wall Street Journal ● Apr. 27, 2026

The beloved children's character ambled into the world in 1926 in a book written by English author A.A.

From Barron's ● Mar. 10, 2026

Sharon — the hairdresser, played by Hilary Swank — learns of Schmitt’s plight and decides to help the family as a focus for her energies after reluctantly attending an A.A. meeting.

From New York Times ● Feb. 22, 2024

All but the last were graduates of the Engineering Department, among whose graduates are also to be numbered A.A.

From The University of Michigan by Wilfred Shaw