Nicaea vs ecumenical council

Nicaea and ecumenical council both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nicaea	Yes	No	No	No
ecumenical council	Yes	No	No	No

As nouns, ecumenical council is a hypernym of Nicaea; that is, ecumenical council is a word with a broader meaning than Nicaea:

Nicaea: the first ecumenical council in 325 which produced the wording of the Nicene Creed and condemned the heresy of Arianism
ecumenical council: (early Christian church) one of seven gatherings of bishops from around the known world under the presidency of the Pope to regulate matters of faith and morals and discipline

As nouns, ecumenical council is a hypernym of Nicaea; that is, ecumenical council is a word with a broader meaning than Nicaea:

Nicaea: the seventh ecumenical council in 787 which refuted iconoclasm and regulated the veneration of holy images
ecumenical council: (early Christian church) one of seven gatherings of bishops from around the known world under the presidency of the Pope to regulate matters of faith and morals and discipline

Nicaea (noun)	ecumenical council (noun)
the first ecumenical council in 325 which produced the wording of the Nicene Creed and condemned the heresy of Arianism	(early Christian church) one of seven gatherings of bishops from around the known world under the presidency of the Pope to regulate matters of faith and morals and discipline
the seventh ecumenical council in 787 which refuted iconoclasm and regulated the veneration of holy images
an ancient city in Bithynia; founded in the 4th century BC and flourished under the Romans; the Nicene Creed was adopted there in 325