rud·dle (rŭdl) also red·dle (rĕdl) or rad·dle (rădl)
Red ocherous iron ore, used in dyeing and marking.
tr.v. rud·dled, rud·dling, rud·dles also red·dled or red·dling or red·dles or rad·dled or rad·dling or rad·dles
To dye or mark with or as if with red ocher: ruddle sheep.
[Probably diminutive of rud, red, from Middle English rudde, from Old English rudu; see reudh- 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.