There are multiple definitions:

1. time of arrival(English)

   • TSAR

2. Technisch Oogheelkundig Assistent(Dutch)

   • Ophthalmology

3. tetracyclic oxindole alkaloid(English)

   • inhibits the real active agents of cat's claw
   • POA
   • Toxicology
   • https://doi.org…rop.2013.04.026