1. Insurance held jointly by two or more insurers.
2. A form of insurance in which a person insures property for less than its full value and agrees to be responsible for the difference.
3. A sum of money paid by a patient to a health care provider after a health insurance company has paid a contractual amount for a covered service, usually a fixed percentage of costs. Coinsurance usually applies after an annual deductible has been paid.
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.