From Longman Dictionary of Contemporary Englishsash windowˈsash ˌwindow noun [countable] British English TBa window consisting of two frames that you open by sliding one up or down, behind or in front of the other
Examples from the Corpus
sash window• Long dark blue silk curtains hung at the elegant sash window overlooking the creek.• It was lit by a large sash window having sixteen panes.• Blanche forced the screwdriver up into the crevice between the two halves of the sash window and heaved. 