transom vs transom window

transom and transom window both are nouns.

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

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

transom and transom window: a window above a door that is usually hinged to a horizontal crosspiece over the door

Other synonyms of transom include fanlight.

transom (noun)	transom window (noun)
a horizontal crosspiece across a window or separating a door from a window over it	a window above a door that is usually hinged to a horizontal crosspiece over the door
a window above a door that is usually hinged to a horizontal crosspiece over the door