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

• 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

Like any tubing mascara, Badi Lash wraps lashes in flexible, smudge-proof polymers that darken and lengthen them. —Sophia Panych, Allure, 16 Sep. 2025

Earlier this year, Norway’s sovereign wealth fund proposed switching to semiannual reporting, reasoning that lengthening the time frame would allow companies to focus on the longer term. —Jeff Cox, CNBC, 15 Sep. 2025

Legislators lengthened the state’s deadline to prosecute rapes of adults from 10 to 15 years. —Willoughby Mariano, ProPublica, 11 Sep. 2025

The line made other minor tweaks as well, such as redesigning its central Roundabout area to offer more indoor lounge space and lengthening the main pool. —Nathan Diller, USA Today, 11 Sep. 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