- a subbranch of the Sino-Tibetan language family, including Thai, Laotian, and Shan
- a member of any of the Southeast Asian peoples speaking these languages
- a member of a people of N Vietnam that speaks a Tai language
- the language of this people
nounpl. Tai, or Tais
- A subfamily of Tai-Kadai languages spoken in southeast Asia and southern China that includes Thai, Lao, and Shan.
- A member of any of the Tai-speaking peoples of Thailand, Myanmar (Burma), Laos, China, and Vietnam.
- IATA airport code for Ta'izz International Airport.
- ICAO code for TACA International Airlines.
- Transports Aériens Intercontinentaux, a now defunct French airline.
- Thai Airways International.
- Toshiba America, Inc..
- Turkish Aerospace Industries, Inc.
- Trifluoromethylaminoindane, a psychoactive drug and serotonin releasing agent.
- Technical analysis indicator.