lesion

noun

le·​sion ˈlē-zhən 

1

: injury, harm

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

ˈlē-zhənd 

adjective

Examples of lesion in a Sentence

Recent Examples on the Web

The researchers also found that AI’s strength in flagging cancerous lesions didn’t carry over to naming the correct diagnosis among many possibilities. — Leslie Baumann, Miami Herald, 22 Oct. 2026

Two of them, the central vein sign and paramagnetic rim lesions, were added to the most recent version of the diagnostic guidelines (published in 2025). — Erica Sloan, Washington Post, 22 Oct. 2026

Those can include advanced MRI sequences to study the lesions more closely, a spinal MRI, or spinal fluid analysis that can identify specific abnormal immune proteins, Brumel said. — Kerry Breen, CBS News, 20 Oct. 2026

Doctors will look for damage in the form of lesions in different areas of the central nervous system, according to the National Multiple Sclerosis Society (NMSS). — ABC News, 20 Oct. 2026

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

Rhymes for lesion

• friesian
• adhesion
• artesian
• cartesian
• cohesion
• elysian
• magnesian
• austronesian
• indonesian
• melanesian
• micronesian
• polynesian

Kids Definition

lesion

noun

le·​sion ˈlē-zhən 

: 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 

: an abnormal change in structure of an organ or part due to injury or disease

especially : one that is circumscribed and well defined

lesioned

-zhənd 

adjective

lesion

2 of 2 transitive verb

: to produce lesions in (as an animal's brain)

Legal Definition

lesion

noun

le·​sion ˈlē-zhən 

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