One of the wedge-shaped stones forming the curved parts of an arch or vaulted ceiling.
[French, from Old French vossoir, from Vulgar Latin *volsōrium, from *volsus, past participle of Latin volvere, to turn, roll; see wel-2 in the Appendix of Indo-European roots.]
(click for a larger image)voussoir
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.