1. Any of numerous often weedy plants of several genera of the composite family, including Cirsium, Carduus, and Onopordum, having prickly leaves and floral bracts.
2. Any of various other prickly plants, such as Russian thistle.
[Middle English, fromOld Englishthistel; see steig- in the Appendix of Indo-European roots.]
(click for a larger image)thistle
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.