telephone circuit vs connexion

telephone circuit and connexion both are nouns.

Word	Noun	Adjective	Verb	Adverb
telephone circuit	Yes	No	No	No
connexion	Yes	No	No	No

As nouns, connexion is a hypernym of telephone circuit; that is, connexion is a word with a broader meaning than telephone circuit:

Other hypernyms of telephone circuit include connecter, connection, connective, connector.

telephone circuit (noun)	connexion (noun)
a telephone connection	the act of bringing two things into contact (especially for communication)
	shifting from one form of transportation to another
	an instrumentality that connects
	the process of bringing ideas or events together in memory or imagination
	a relation between things or events (as in the case of one causing the other or sharing features with it)
	a connecting shape