Nah or NAH may refer to:

• Naha Airport (Indonesia) (IATA airport code: NAH), Tahuna, Sangir Islands, North Sulawesi, Indonesia
• Nahuatl (ISO language code: nah), a Uto-Aztecan language spoken in Mexico and El Salvador
• Nehbandan or Nah, a city in South Khorasan Province, Iran
• Ix Ek' Naah, a Mayan queen
• Sodium hydride, whose chemical formula is NaH
• a variation of "no", as in "yes and no", common especially in Australian English

The Book of Nahum is the seventh book of the 12 minor prophets of the Hebrew Bible. It is attributed to the prophet Nahum, and was probably written in Jerusalem in the 7th century BC.

Naha Airport is an airport serving the locality of Tahuna, in the Sangir Islands, part of the North Sulawesi province of Indonesia. The airport is connected to Manado by weekly Trigana Air Service flights.

Sodium hydride is the chemical compound with the empirical formula NaH. It is primarily used as a strong, yet combustable base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na⁺ and H^- ions, in contrast to the more molecular hydrides such as borane, methane, ammonia and water. It is an ionic material that is insoluble in organic solvents (although soluble in molten Na), consistent with the fact that H^- remains an unknown anion in solution. Because of the insolubility of NaH, all reactions involving NaH occur at the surface of the solid.