a supplementary window sash for protecting a window against drafts, driving rain, etc.
Origin of storm window
First recorded in 1885–90
Also called storm sash.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for storm window
Historical Examples of storm window
an additional window fitted to the outside of an ordinary window to provide insulation against wind, cold, rain, etc
a type of dormer window
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012