mask vs welder's mask

mask and welder's mask both are nouns.

Word	Noun	Adjective	Verb	Adverb
mask	Yes	No	Yes	No
welder's mask	Yes	No	No	No

As nouns, welder's mask is a hyponym of mask; that is, welder's mask is a word with a more specific, narrower meaning than mask:

Other hyponyms of mask include face mask, gas helmet, gasmask, respirator.

mask (noun)	welder's mask (noun)
activity that tries to conceal something	a mask that you wear for protection when doing welding
a covering to disguise or conceal the face
a protective covering worn over the face
a party of guests wearing costumes and masks

mask (verb)	welder's mask (verb)
put a mask on or cover with a mask
shield from light
cover with a sauce
hide under a false appearance
make unrecognizable