TG or Tg may stand for: Math and science tangent an alternative used in China and Russia (mathematical abbreviation). Tarski-Grothendieck set theory, an axiomatic set theory. Tg, glass transition temperature Thermogravimetry Thyroglobulin (a protein) a teragram, a unit of mass equal to one megatonne Triglyceride Transmission gate Computer technology Windows TG, a fictional operating system featured in the show Mega64 Traditional game, a computer adaptation of a board or card game. Th… (More on Tg)