Definition of "lesion"

(pathology) A wound or injury.

(medicine) An infected or otherwise injured or diseased organ or part, especially such on a patch of skin.  examples

(biochemistry) Any compound formed from damage to a nucleic acid.  examples

(law) Injury or an unfair imbalance in a commutative contract wherein the consideration is less than half of the market value, which then serves as a basis for the injured party to sue to rescind the agreement.  examples

(transitive) To wound or injure, especially in an experiment or other controlled procedure.  examples