solder vs join

solder and join both are nouns.

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

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

Other hypernyms of solder include conjoin.

solder (noun)	join (noun)
an alloy (usually of lead and tin) used when melted to join two metal surfaces	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

solder (verb)	join (verb)
join or fuse with solder	make contact or come together
	cause to become joined or linked
	become part of; become a member of a group or organization
	come into the company of
	be or become joined or united or linked