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

His telomeres, protective caps on chromosomes, lengthened in space, only to shorten rapidly upon return. —Kaif Shaikh, Interesting Engineering, 16 Oct. 2025

The Airwrap Diffuse now features a wide-tooth comb, a new diffuser, and a round volumizing brush for good measure — here to lengthen your curls, reduce their overall frizz, and boost your mane’s fullness, respectively. —Stacia Datskovska, Footwear News, 16 Oct. 2025

These circuitous routes greatly lengthen mission durations and limit launches to tight windows. —Big Think, 15 Oct. 2025

Each year, the mining site crept farther south as deposits dwindled, lengthening her father’s commute. —Literary Hub, 10 Oct. 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