show window vs shop window

show window and shop window both are nouns.

Word	Noun	Adjective	Verb	Adverb
show window	Yes	No	No	No
shop window	Yes	No	No	No

As nouns, show window and shop window are synonyms defined as:

show window and shop window: a window of a store facing onto the street; used to display merchandise for sale in the store

Other synonyms of show window include display window, shopwindow.

show window (noun)	shop window (noun)
a window of a store facing onto the street; used to display merchandise for sale in the store	a window of a store facing onto the street; used to display merchandise for sale in the store
a setting in which something can be displayed to best effect