lengthen

verb

length·​en ˈleŋ(k)-thən How to pronounce lengthen (audio)
ˈlen(t)-
lengthened; lengthening
ˈleŋ(k)th-niŋ, 
ˈlen(t)th-;
  ˈleŋ(k)-thə- How to pronounce lengthen (audio)
ˈlen(t)-
Synonyms of lengthennext

transitive verb

: to make longer

intransitive verb

: to grow longer
lengthener
ˈleŋ(k)th-nər, 
ˈlen(t)th-;
  ˈleŋ(k)-thə- How to pronounce lengthen (audio)
ˈlen(t)-
noun

Synonyms of lengthen

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Long-range plans have called for one day to lengthen the Dunes Kankakee Trail 27 miles all the way to Kouts in southern Porter County. — Jim Woods, Chicago Tribune, 27 Oct. 2026 Researchers found that New York state’s season with temperatures suitable for mosquitoes to transmit West Nile virus lengthened by an average of 20 days between 1999 and 2024. — Kylee Rae Noel, The Conversation, 27 Oct. 2026 Longini explained that climate change is increasing mosquito populations and lengthening their active seasons, contributing to dengue’s spread globally. — Alex Deluca, Washington Post, 23 Oct. 2026 Diversifying out of China lengthened it, vendors have added their own buffers into development to absorb retailer changes, and physical disruptions like the Red Sea reroute stretch it further, so the calendar is already long before goods even move. — Arthur Zaczkiewicz, Footwear News, 23 Oct. 2026 See All Example Sentences for lengthen

Word History

First Known Use

14th century, in the meaning defined at transitive sense

Time Traveler
The first known use of lengthen was in the 14th century

Rhymes for lengthen

See All Rhymes for lengthen

Browse Nearby Words

length-breadth index
lengthen
lengthener
See all Nearby Words

Cite this Entry

“Lengthen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lengthen. Accessed 1 Nov. 2026.

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Kids Definition

lengthen

verb
length·​en ˈleŋ(k)-thən How to pronounce lengthen (audio)
ˈlen(t)-
lengthened; lengthening ˈleŋ(k)th-(ə-)niŋ How to pronounce lengthen (audio)
ˈlen(t)th-
: to make or become longer
lengthener
ˈleŋ(k)th-(ə-)nər How to pronounce lengthen (audio)
ˈlen(t)th-
noun
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