AIDS → Acquired immunodeficiency syndrome

Artificial Insemination by Donor, a type of human artificial insemination in which donor sperm are provided by an individual other than the recipient's partner

USAID → United States Agency for International Development

Activation-Induced (Cytidine) Deaminase, an enzyme

Association for India's Development, an American/Indian non-profit organization

Americans for Informed Democracy, an American non-profit organization

Algebraic Interpretive Dialogue, an implementation of JOSS II for the PDP-10

Automatic Interaction Detection, a precursor to, and component of CHAID