lesion /ˈliːʒən/noun 4verb 1forms 3 noun4 •A wound or injury. •An infected or otherwise injured or diseased organ or part, especially such on a patch of skin. •Any compound formed from damage to a nucleic acid. •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. verb1 •To wound or injure, especially in an experiment or other controlled procedure. formslesioned · lesioning · lesions