Lengthen/ˈleŋkθən/ Definition 1 of 3Pro Tip 1/3Physical objects Often used when discussing the dimensions or size of tangible, physical things. I need to lengthen the table with an additional leaf for the party. Pro Tip 2/3Visual impact Enhancing appearance by changing the length of an object or part of it. A high-waisted belt will lengthen the look of your legs. Pro Tip 3/3Attire adjustments Commonly used to describe alterations in clothing for a better fit or style. I'll have to lengthen these pants to wear them with my new boots.