-tion/-sion

turns a verb into a noun naming an action, process, or result

Spelled -tion, -sion, -ation · -tiō/-tiōn- 'action, process, or result'

Latin -tiō named an act or result: creation is creating made noun, expansion is expanding, and admission is admitting.

Words built from it

creation — the act of making something new, or what is made
create + -tion (action or result)
expansion — the process of becoming larger
expand + -sion (action or result)
persuasion — the act of convincing someone
persuade + -sion (action or result)
observation — the act of watching carefully, or something noticed
observe + -ation (action or result)
declaration — a formal or definite statement
declare + -ation (action or result)
admission — an acknowledgment or permission to enter
admit + -sion (action or result)

-ous — turns a noun or root into an adjective meaning full of, having, or characterized by it
-phobia/-phile — forms names for intense fears or aversions, or for people and feelings marked by strong fondness
-ward — turns a place or direction into a word showing movement or orientation that way