-ion
Nouns ending in -ion are almost always die.
German does not build these — the words arrived whole.The words came from Latin.
Examples
- die Religion
- die Region
- die Union
- die Legion
- die Rebellion
Plural
- die Religion → die Religionen
One exception
-tion and -sion never break. On the bare -ion, der Skorpion does.
- der Skorpion
Same letters, different ending
- das Stadion
- der Spion
- der Lampion