DCHP-1 Online
double window 
a storm window; a removable glazed frame put on in the fall and taken off in the spring, to help keep out the cold.
- 1837 (1961) Toward the end of October Anne wondered whether the house would be cold in the winter because of the lack of "double windows".
- 1871 On entering the room I found a scorching stove, and the temperature up to about 70°; and as there were double windows, and no aperture for the ingress of fresh air, and the place was crammed full, I began to fear lest we should be stifled.
- 1958 It is possible that the prevalence of double window in Montreal English is reflected in the speech of French-speaking Montrealers since many of them use the term fenêtre double to refer to a window placed over another for extra protection during the winter.
- 1837 (1961) Toward the end of October Anne wondered whether the house would be cold in the winter because of the lack of "double windows".