Ionian order vs Ionic order

Ionian order and Ionic order both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ionian order	Yes	No	No	No
Ionic order	Yes	No	No	No

As nouns, Ionian order and Ionic order are synonyms defined as:

Ionian order and Ionic order: the second Greek order; the capital is decorated with spiral scrolls

Ionian order (noun)	Ionic order (noun)
the second Greek order; the capital is decorated with spiral scrolls	the second Greek order; the capital is decorated with spiral scrolls