lesion

noun

le·​sion ˈlē-zhən How to pronounce lesion (audio)
Synonyms of lesionnext
1
2
: an abnormal change in structure of an organ or part due to injury or disease
especially : one that is circumscribed (see circumscribe sense 1) and well-defined
lesioned adjective

Examples of lesion in a Sentence

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.
In another case, a 10-year-old girl contracted horrible lesions on 10 percent of her body — mostly on her legs — after contact with giant hogweed. Natalie Krebs, Outdoor Life, 26 Mar. 2026 In the mid-stage study, 75% of participants injected once every three months with Apogee’s drug, called zumilokibart, maintained at least a 75% improvement in the extent and severity of skin lesions — a metric dubbed EASI-75 — at one year. Adam Feuerstein, STAT, 23 Mar. 2026 In rare cases, mpox can lead to eye infections, severe rash, painful skin lesions and neurological problems. Melissa Rudy, FOXNews.com, 16 Mar. 2026 Last summer, Brossoit and doctors, after examining his right hip, found the root cause of the knee pain — a cam lesion on the head of his femur that was causing issues with cartilage inside the joint. Curtis Pashelka, Mercury News, 15 Mar. 2026 See All Example Sentences for lesion

Word History

Etymology

Middle English, from Anglo-French, from Latin laesion-, laesio, from laedere to injure

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of lesion was in the 15th century

Browse Nearby Words

Cite this Entry

“Lesion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lesion. Accessed 31 Mar. 2026.

Kids Definition

lesion

noun
le·​sion ˈlē-zhən How to pronounce lesion (audio)
: a change in the structure of a bodily organ or part due to injury or disease
especially : an injured or diseased spot or area clearly marked off from healthy tissue around it

Medical Definition

lesion

1 of 2 noun
le·​sion ˈlē-zhən How to pronounce lesion (audio)
: an abnormal change in structure of an organ or part due to injury or disease
especially : one that is circumscribed and well defined
lesioned adjective

lesion

2 of 2 transitive verb
: to produce lesions in (as an animal's brain)

Legal Definition

lesion

noun
le·​sion ˈlē-zhən How to pronounce lesion (audio)
in the civil law of Louisiana : loss from failure to receive a threshold amount or value (as one-half market value) for immovable property conveyed or transferred by a commutative contract (as a sale or exchange)

called also lesion beyond moiety

compare unjust enrichment
Etymology

Anglo-French, damage, injury, from Latin laesio, from laedere to injure

More from Merriam-Webster on lesion

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster