spandril vs spandrel

spandril and spandrel both are nouns.

Word	Noun	Adjective	Verb	Adverb
spandril	Yes	No	No	No
spandrel	Yes	No	No	No

As nouns, spandril and spandrel are synonyms defined as:

spandril and spandrel: an approximately triangular surface area between two adjacent arches and the horizontal plane above them

spandril (noun)	spandrel (noun)
an approximately triangular surface area between two adjacent arches and the horizontal plane above them	an approximately triangular surface area between two adjacent arches and the horizontal plane above them