actinium, Ac, atomic number 89 (noun)

a radioactive element of the actinide series; found in uranium ores

alternating current, AC, alternating electric current (noun)

an electric current that reverses direction sinusoidally

"In the US most household current is AC at 60 cycles per second"

ac (Conjunction)

But.

Ac (Noun)

Air-conditioning.

Ac (Noun)

Altocumulus clouds.

Ac (Noun)

The Acura Legend.

ac

.ac is the Internet country code top-level domain for Ascension Island. It is administered by NIC.AC, a subsidiary of the Internet Computer Bureau based in the United Kingdom. Registration for this domain is open to anyone. The registry accepts registrations of internationalized domain names. .ac is marketed by some domain-brokers as a domain for the city of Aachen in Germany, using the analogy to the automotive license plate designation for the city.