from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Any of various thistles of the genus Centaurea, having variously colored flowers grouped in a head with a spiny involucre.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Any of various common weeds of the genus Centaurea

from the GNU version of the Collaborative International Dictionary of English

  • n. The black centaury (Centaurea nigra); -- so called from the knoblike heads of flowers. Called also bullweed.

from The Century Dictionary and Cyclopedia

  • n. A general name for plants of the genus Centaurea of the composite family, as C. Calcitrapa, the star-thistle, and C. Cyanus, bachelor's-buttons.
  • n. Specifically, C. nigra, also called buttonweed, hardhead, loggerhead, and by various other names.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. any of various plants of the genus Centaurea having purple thistlelike flowers


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English knopwed : knop, knob; see knop + wed, weed; see weed1.

from Wiktionary, Creative Commons Attribution/Share-Alike License

Alteration of knopweed.


  • She had walked the trail years ago, long before Hinkley Point C had reached its earliest draft on the planning board, and she had seen the blue and copper butterflies and the pale flax and the golden birds' foot trefoil and the royal purple proud-headed knapweed.

    Margaret Drabble | Trespassing

  • We saw a lot of wild garlic, scabia, buddleia, bird's-foot trefoil and greater knapweed.

    Country diary: Longburton, Dorset

  • I slowly realise that they are stationed right across this marsh in almost every spike of last year's marsh thistle and black knapweed.

    Country diary: Claxton, Norfolk

  • A few swallows swoop low and the rank green is broken by pink hemp agrimony, cream meadowsweet, blue tufted vetch and purple knapweed.

    Country diary

  • In an open woodland glade on a bank of old limestone spoil covered in grasses, black knapweed, wild basil, pyramidal orchids and harebells, many butterflies were making the most of the sunshine, and the air was full of their strobing brown, gold and white wings.

    Country diary: Wenlock Edge

  • Somehow their snapping flight filled the space of the clearing and then they landed on dark purple knapweed flowers to feed.

    Country diary: Wenlock Edge

  • Hemp agrimony, bird's-foot trefoil and knapweed attracted the attention of commas, common blues, red admirals and the only painted ladies we've encountered so far this year.

    Country diary: Durham coast

  • Mauve scabious and darker purple knapweed wave their heads in the aftermath of a summer thunderstorm.

    Butterflies: out of the blue

  • Researchers in Michigan released bugs that feed on spotted knapweed earlier this year.

    Will Killing This Invasive Plant Harm Bees?

  • Michigan officials don't expect to wipe out knapweed; the hope is to pare it back.

    Will Killing This Invasive Plant Harm Bees?


Log in or sign up to get involved in the conversation. It's quick and easy.