yion
In what language?
Lion. Zion.
One such word is mansion.
Some three letter words that start with I are ion, ice, ire, and imp.
Occupation
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.
Radion
occupation
tion