attach vs join

attach is not a noun while join is a noun.

Word	Noun	Adjective	Verb	Adverb
attach	No	No	Yes	No
join	Yes	No	Yes	No

As verbs, join is a hypernym of attach; that is, join is a word with a broader meaning than attach:

Other hypernyms of attach include conjoin.

attach (noun)	join (noun)
	a set containing all and only the members of two or more given sets
	the shape or manner in which things come together and a connection is made

attach (verb)	join (verb)
become attached	make contact or come together
cause to be attached	cause to become joined or linked
be attached; be in contact with	become part of; become a member of a group or organization
take temporary possession of as a security, by legal authority	come into the company of
create social or emotional ties	be or become joined or united or linked