An upper undergarment, typically having short or no sleeves, worn next to the skin under a shirt.(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 "undershirt" in a sentence
"Listen, I'm looking at this photo of Ripley in her underwear, from the original -- the undershirt is the same, but these briefs -- I think maybe they aren't really women's briefs, I think these are men's, like a Speedo version of undies."
"During the winter a shirt with an undershirt is usually sufficient except on overcast and colder days when a light jacket will help."
"But from my personal experience during the spring, summer and fall a shirt without undershirt is usually comfortable except on the very hottest days."