stretcher vs copestone

stretcher and copestone both are nouns.

Word	Noun	Adjective	Verb	Adverb
stretcher	Yes	No	No	No
copestone	Yes	No	No	No

As nouns, stretcher and copestone are synonyms defined as:

Other synonyms of stretcher include capstone, coping stone.

stretcher (noun)	copestone (noun)
a litter for transporting people who are ill or wounded or dead; usually consists of a sheet of canvas stretched between two poles	a stone that forms the top of wall or building
a stone that forms the top of wall or building	a final touch; a crowning achievement; a culmination
a mechanical device used to make something larger (as shoes or gloves) by stretching it
a wooden framework on which canvas is stretched and fixed for oil painting