- lengthen⇄lengthen, transitive verb.
to make longer.
Ex. A tailor can lengthen your trousers. - lengthen⇄noun lengthener.
- lengthen⇄v.i. to become or grow longer.
Ex. the shadows lengthening as the vapours rise (John Dryden). Your legs have lengthened a great deal since you were five years old.