skeen arch vs diminished arch

skeen arch and diminished arch both are nouns.

Word	Noun	Adjective	Verb	Adverb
skeen arch	Yes	No	No	No
diminished arch	Yes	No	No	No

As nouns, skeen arch and diminished arch are synonyms defined as:

skeen arch and diminished arch: an arch whose height is less than half its width

Other synonyms of skeen arch include scheme arch, skene arch.

skeen arch (noun)	diminished arch (noun)
an arch whose height is less than half its width	an arch whose height is less than half its width