solder vs hard solder

solder and hard solder both are nouns.

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

As nouns, hard solder is a hyponym of solder; that is, hard solder is a word with a more specific, narrower meaning than solder:

solder: an alloy (usually of lead and tin) used when melted to join two metal surfaces
hard solder: solder that contains copper; melts at a relatively high temperature; used for brazing

Other hyponyms of solder include silver solder, soft solder.

solder (noun)	hard solder (noun)
an alloy (usually of lead and tin) used when melted to join two metal surfaces	solder that contains copper; melts at a relatively high temperature; used for brazing

solder (verb)	hard solder (verb)
join or fuse with solder