lengthen

verb

length·​en ˈleŋ(k)-thən 

ˈlen(t)-

lengthened; lengthening

ˈleŋ(k)th-niŋ, 

ˈlen(t)th-;

  ˈleŋ(k)-thə- 

ˈlen(t)-

transitive verb

: to make longer

intransitive verb

: to grow longer

lengthener

ˈleŋ(k)th-nər, 

ˈlen(t)th-;

  ˈleŋ(k)-thə- 

ˈlen(t)-

noun

Synonyms of lengthen

• extend
• prolong
• increase
• stretch
• elongate

Choose the Right Synonym for lengthen

extend, lengthen, prolong, protract mean to draw out or add to so as to increase in length.

extend and lengthen imply a drawing out in space or time but extend may also imply increase in width, scope, area, or range.

extend a vacation

extend welfare services

lengthen a skirt

lengthen the workweek

prolong suggests chiefly increase in duration especially beyond usual limits.

prolonged illness

protract adds to prolong implications of needlessness, vexation, or indefiniteness.

protracted litigation

Examples of lengthen in a Sentence

The days lengthened with the approach of spring.

Proper care will lengthen the life of the engine.

lengthen a pair of trousers

Recent Examples on the Web

Air pollution and biothermal stress may be lengthening human pregnancies, and between 2016 and 2024, the brains of dead humans exhibited a 50 percent increase in microplastic levels. —Victor J. Blue, Harpers Magazine, 23 Nov. 2025

Old standbys and new treatments Topical minoxidil, also known as Rogaine, is a foam available over-the-counter that lengthens the growth phase of the hair cycle, keeping more hair on the head at any one time. —Sydney Lupkin, NPR, 23 Nov. 2025

Because of shifting consumer trends, many stores have lengthened their opportunities for discounts from one day to weeks before and after Black Friday with online and in-store deals. —Paige Moore, AZCentral.com, 22 Nov. 2025

These high-rise flares are made with stretchy, curve-hugging denim that lifts, smooths, and lengthens your legs in that magical Spanx way. —Jeaneen Russell, PEOPLE, 21 Nov. 2025

Word History

First Known Use

14th century, in the meaning defined at transitive sense

Rhymes for lengthen

• strengthen

Kids Definition

lengthen

verb

length·​en ˈleŋ(k)-thən 

ˈlen(t)-

lengthened; lengthening ˈleŋ(k)th-(ə-)niŋ 

ˈlen(t)th-

: to make or become longer

lengthener

ˈleŋ(k)th-(ə-)nər 

ˈlen(t)th-

noun