Lion.
Zion.
In what language?
One such word is mansion.
Occupation
yion
Battalion.
A fourteen (14) letter word that ends with ion or tion: administration
Words ending with ion would include competition, perdition, rendition, nation, vacation, etc., all of which are nouns.
tion
occupation
Radion
Ion.
"differentiation" is a noun. (Most words ending in "ion" are nouns. )