Definitions

1. interjection

a loud, inarticulate exclamation, often expressing excitement, anger, or pain.

“She let out an ‘aa’ of frustration when she dropped her phone.”

2. noun

a unit of measurement, especially for sound, equal to the frequency of 110 Hz.

“The concert hall’s acoustics were measured in aas.”

3. prefix

a prefix used in chemistry to denote a series of substances, such as astatine (At or At) and actinium (Ac or Ac).

“The periodic table listed the actinides as Ac.”

4. abbreviation

an abbreviation for ‘amperes alternating’, used to describe alternating current.

“The electrical engineer worked with aas in the new power grid.”

5. noun

a term used in phonetics to describe a long, low vowel sound.

“The linguist analyzed the aa sound in the native language.”