Why is it die Rotation?

Rotation ends in -ion, and almost all nouns ending in -ion are feminine: in a German dictionary, 94% of them take die.

All nouns ending in -ion
Sense 1
die

Meaning

[1] circular movement around an axis

[1] kreisförmige Bewegung um eine Achse

Examples

[1] The rotation of the earth ensures day and night

[1] Die Rotation der Erde sorgt für Tag und Nacht.

Declension

1 Singular Plural
Nominativ die Rotation die Rotationen
Genitiv der Rotation der Rotationen
Dativ der Rotation den Rotationen
Akkusativ die Rotation die Rotationen

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary