attachment vs connection

attachment and connection both are nouns.

Word	Noun	Adjective	Verb	Adverb
attachment	Yes	No	No	No
connection	Yes	No	No	No

As nouns, connection is a hypernym of attachment; that is, connection is a word with a broader meaning than attachment:

attachment: the act of fastening things together
connection: the act of bringing two things into contact (especially for communication)

Other hypernyms of attachment include connexion, joining.

As nouns, connection is a hypernym of attachment; that is, connection is a word with a broader meaning than attachment:

Other hypernyms of attachment include connecter, connective, connector, connexion.

attachment (noun)	connection (noun)
the act of fastening things together	the act of bringing two things into contact (especially for communication)
the act of attaching or affixing something	shifting from one form of transportation to another
faithful support for a cause or political party or religion	an instrumentality that connects
a supplementary part or accessory	the process of bringing ideas or events together in memory or imagination
a connection that fastens things together	a supplier (especially of narcotics)
a writ authorizing the seizure of property that may be needed for the payment of a judgment in a judicial proceeding	(usually plural) a person who is influential and to whom you are connected in some way (as by family or friendship)
a feeling of affection for a person or an institution	a relation between things or events (as in the case of one causing the other or sharing features with it)
	a connecting shape
	the state of being connected