Any of various pathological or traumatic changes in a bodily organ or tissue, including tumors, ulcers, sores, and wounds.
tr.v. le·sioned, le·sion·ing, le·sions
To cause a lesion to form on or in.
[Middle English lesioun, from Old French lesion, from Latin laesiō, laesiōn-, from laesus, past participle of laedere, to injure.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.