dormer vs dormer window

dormer and dormer window both are nouns.

Word	Noun	Adjective	Verb	Adverb
dormer	Yes	No	No	No
dormer window	Yes	No	No	No

As nouns, dormer and dormer window are synonyms defined as:

dormer and dormer window: a gabled extension built out from a sloping roof to accommodate a vertical window

dormer (noun)	dormer window (noun)
a gabled extension built out from a sloping roof to accommodate a vertical window	a gabled extension built out from a sloping roof to accommodate a vertical window
	the window in a gabled extension built to accommodate a window