lettering vs inscription

lettering and inscription both are nouns.

Word	Noun	Adjective	Verb	Adverb
lettering	Yes	No	No	No
inscription	Yes	No	No	No

As nouns, lettering and inscription are synonyms defined as:

lettering and inscription: letters inscribed (especially words engraved or carved) on something

lettering (noun)	inscription (noun)
letters inscribed (especially words engraved or carved) on something	the activity of inscribing (especially carving or engraving) letters or words
	letters inscribed (especially words engraved or carved) on something
	a short message (as in a book or musical work or on a photograph) dedicating it to someone or something