Need the correct grammatical term for "...tion"

[Pennies]

I'm writing about mediation, relaxation, visualisation etc and I want to use the term that describes the final "tion" syllable of each word.

Anyone know it?

Noun-forming suffixes.

nominalisation - if you mean the act of turning a verb into a noun. Though, it doesn't have to take the form of 'tion'.

very handy for essays

Much gratification!