copestone vs stretcher

copestone and stretcher both are nouns.

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

As nouns, copestone and stretcher are synonyms defined as:

Other synonyms of copestone include capstone, coping stone.

copestone (noun)	stretcher (noun)
a stone that forms the top of wall or building	a litter for transporting people who are ill or wounded or dead; usually consists of a sheet of canvas stretched between two poles
a final touch; a crowning achievement; a culmination	a stone that forms the top of wall or building
	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