dioecious vs dioecian

dioecious and dioecian both are adjectives.

Word	Noun	Adjective	Verb	Adverb
dioecious	No	Yes	No	No
dioecian	No	Yes	No	No

As adjectives, dioecious and dioecian are synonyms defined as:

dioecious and dioecian: having male and female reproductive organs in separate plants or animals

dioecious (adjective)	dioecian (adjective)
having male and female reproductive organs in separate plants or animals	having male and female reproductive organs in separate plants or animals