A window set vertically into a small gable projecting from a sloping roof.(noun)
The gable holding such a window.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "dormer" in a sentence
"I used to pretend I was a lighthouse keeper and the dormer was my lighthouse, and I’d look out for boats about to crash on our ront lawn, which I pretended was a treacherous beach."
"The house rose three stories, the third being a steep roof with five dormer windows across."
"The left portion sat low, with a simple sloping roof and dormer windows for its second floor."