1. A flat disk of metal ready for stamping as a coin; a coin blank.
2. A small shallow metal container in which a radioactive substance is deposited for measurement of its activity.
[ Diminutive of planch, flat plate, slab, from Middle English plaunche, plank, from Old French planche, from Late Latin planca, from feminine of Latin plancus, flat; see plāk-1 in the Appendix of Indo-European roots.]
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.