window glass vs pane

window glass and pane both are nouns.

Word	Noun	Adjective	Verb	Adverb
window glass	Yes	No	No	No
pane	Yes	No	No	No

As nouns, window glass and pane are synonyms defined as:

Other synonyms of window glass include pane of glass.

window glass (noun)	pane (noun)
sheet glass cut in shapes for windows or doors	sheet glass cut in shapes for windows or doors
	a panel or section of panels in a wall or door
	street name for lysergic acid diethylamide