n. pl. me·nis·ci(-nĭsī, -kī, -kē) or me·nis·cus·es
1. A crescent-shaped body.
2. A concavo-convex lens.
3. The curved upper surface of a nonturbulent liquid in a container that is concave if the liquid adheres to the container walls and convex if it does not.
4. A cartilage disk that acts as a cushion between the ends of bones that meet in a joint.
[New Latin mēniscus, from Greek mēniskos, diminutive of meis, mēn-, crescent moon; see mē-2 in the Appendix of Indo-European roots.]
me·niscal (-kəl), me·niscate′ (-kăt′), me·niscoid′ (-koid′), men′is·coidal (mĕn′ĭs-koidl) adj.
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.