Antarctica, DAFIF 0413 / DIA 65-18 / FIPS PUB 10-4 territory code and obsolete NATO digram

Armenia, WMO country code

Aymara language (ISO 639 alpha-2 language code)

Ay, a pharaoh of Ancient Egypt

Finnair, IATA airline designator

Ay, Marne, in the Marne département, Champagne-Ardenne région

Murat Ay, a Turkish cartoonist

General Instrument AY-3-8910, a computer sound chip common in the 1980s and often referred to as the "AY chip"

Ay kingdom, an ancient dynasty in India

Ay is a correct transliteration of Volapük Ä, and ay is correct for ä