NAD can refer to:

• Nicotinamide adenine dinucleotide, or NADH, a coenzyme and signaling molecule, whose oxidated form is NAD+
• National Appeals Division, an agency within the United States Department of Agriculture
• National Association of the Deaf, a non-profit advocacy organization
• NAD Electronics, a Canadian audio equipment manufacturer
• Namibian dollar, the currency of the African nation of Namibia
• North American Datum, a series of geographic coordinate systems
• New Animal Drug, a regulatory category under section 512 of the United States Food, Drug and Cosmetics Act.
• Native Americans at Dartmouth College, one of the Dartmouth College student groups.
• New Age Diamonds, a company producing cultured / synthetic diamonds of new age\
• National Advertising Division
• Network Access Device, a device in mobile phones that finds the shortest route for a connection.
• National Animation and Design Centre, a 3D animation school in Montreal, Canada.

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