Barnaby's thistle

noun

Bar·​na·​by's thistle

ˈbärnəbēz-

: any of several weeds of the genus Centaurea

especially : a European herb (C. solstitialis) adventive in the eastern U.S. and having a winged stem and tomentose leaves

Word History

Etymology

from Barnaby (day), the time of its flowering

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!