Alcyone vs Halcyon

Alcyone and Halcyon both are nouns.

Word	Noun	Adjective	Verb	Adverb
Alcyone	Yes	No	No	No
Halcyon	Yes	No	No	No

As nouns, Alcyone and Halcyon are synonyms defined as:

Alcyone and Halcyon: (Greek mythology) a woman who was turned into a kingfisher

Alcyone (noun)	Halcyon (noun)
(Greek mythology) a woman who was turned into a kingfisher	a large kingfisher widely distributed in warmer parts of the Old World
	(Greek mythology) a woman who was turned into a kingfisher