noun

• (medicine) Initialism of transcutaneous energy transmission system: an experimental subcutaneous device for generating current in heart patients.
  "TETS however, has the problems of fluctuation of coupling factor and load resistance. TETS must be controlled to ensure stable power transmission."
• (organic chemistry) Abbreviation of tetramethylenedisulfotetramine.
  "TETS binds noncompetitively and irreversibly to GABA receptors on neuronal cell membranes and blocks chloride channels."

name

• (UK, railway) Initialism of Trains Entering Terminal Stations: a failsafe device for stopping trains that are entering a station at the end of a railway line.
  "The driver had three hundred quid in his pocket when he died - he was going to put a deposit on a car for his daughter after his shift. That's not the action of a suicide. I suppose some good came out of it, with TETS."

noun

• (UK, informal) A bottle or serving of Tetley's beer.
  "A good pint of Tetleys pulled through the auto vac system, which meant pulling three or four pints to create a single pint, was second to none. Outside Yorkshire, and going south, this system was used infrequently and, consequently, a pint of Tets served elsewhere would be very ordinary."