halftone engraving vs photoengraving

halftone engraving and photoengraving both are nouns.

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

As nouns, halftone engraving and photoengraving are synonyms defined as:

halftone engraving and photoengraving: an engraving used to reproduce an illustration

Other synonyms of halftone engraving include halftone.

halftone engraving (noun)	photoengraving (noun)
an engraving used to reproduce an illustration	an engraving used to reproduce an illustration