When something lengthens or when you lengthen it, it lasts for a longer time than it did previously. Vacations have lengthened and the work week has shortened The council does not support lengthening the school day to fit in other activities. shorten. to make something longer or to become longer shorten
When something lengthens or when you lengthen it, it increases in length. The evening shadows were lengthening She began to walk faster, but he lengthened his stride to keep up with her shorten