halftone engraving vs engraving

halftone engraving and engraving both are nouns.

Word	Noun	Adjective	Verb	Adverb
halftone engraving	Yes	No	No	No
engraving	Yes	No	No	No

As nouns, engraving is a hypernym of halftone engraving; that is, engraving is a word with a broader meaning than halftone engraving:

halftone engraving (noun)	engraving (noun)
an engraving used to reproduce an illustration	making engraved or etched plates and printing designs from them
	a block or plate or other hard surface that has been engraved
	a print made from an engraving