sash vs window sash

sash and window sash both are nouns.

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

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

sash and window sash: a framework that holds the panes of a window in the window frame

sash (noun)	window sash (noun)
a framework that holds the panes of a window in the window frame	a framework that holds the panes of a window in the window frame
a band of material around the waist that strengthens a skirt or trousers