Find the word definition

Wiktionary
trifluoromethanesulfonic acid

n. (context organic compound English) The very strong sulfonic acid CF3SO3H that is used in organic synthesis, where it is known as triflic acid

Wikipedia
Trifluoromethanesulfonic acid

Trifluoromethanesulfonic acid, also known as triflic acid, TFMS, TFSA, HOTf or TfOH, is a sulfonic acid with the chemical formula CFSOH. It is one of the strongest acids. Triflic acid is mainly used in research as a catalyst for esterification. It is a hygroscopic, colorless, slightly viscous liquid which is soluble in polar solvents.