aa

or a·'a, 'a·'a

[ ah-ah ]

noun

basaltic lava having a rough surface.

Origin of aa

First recorded in 1855–60; from Hawaiian ʿaʿā

Compare pahoehoe.

Other definitions for a̅a̅ (2 of 7)

a̅a̅

Symbol.

(in prescriptions) ana².

Origin of a̅a̅

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

Other definitions for AA (3 of 7)

AA¹

abbreviation

administrative assistant.

Other definitions for AA (4 of 7)

AA²

Symbol.

a proportional shoe width size, narrower than A and wider than AAA.
the smallest proportional brassiere cup size.

a quality rating for a corporate or municipal bond, lower than AAA and higher than A.
Electricity. a battery size for 1.5-volt dry cells: diameter, 0.6 inch (1.4 centimeters); length, 2 inches (5 centimeters).
British. a designation for motion pictures certified as unsuitable for children under 14 unless accompanied by an adult.: Compare A³ (def. 10), U⁵ (def. 6), X³ (def. 9).

Other definitions for a.a. (5 of 7)

a.a.

abbreviation

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

Other definitions for A.A. (6 of 7)

A.A.¹

or AA

[ ey-ey ]

abbreviation, noun

Alcoholics Anonymous.

Other definitions for A.A. (7 of 7)

A.A.²

abbreviation

antiaircraft.: Also AA
Associate in Accounting.

Associate of Arts.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

British Dictionary definitions for aa (1 of 3)

aa¹

/ (ˈɑːɑː) /

noun

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

Origin of aa

Hawaiian

British Dictionary definitions for aa (2 of 3)

aa²

abbreviation for

ana 1

British Dictionary definitions for AA (3 of 3)

abbreviation for

Alcoholics Anonymous
anti-aircraft

Architectural Association
(in Britain) Automobile Association
(in Britain) Advertising Association

symbol for

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for aa

[ ä′ä ]

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. See Note at pahoehoe.

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