any of various plants (as genera Onopordum, Cirsium, and Cnicus) of the composite family, with prickly leaves and heads of white, purple, pink, or yellow flowers; esp., the Scotch thistle (O. acanthium) with white down and lavender flowers
Origin of thistleMiddle English thistel from OE, akin to German distel from Indo-European base an unverified form (s)teig-, a point from source stick, Sanskrit tiktá, sharp
- Any of numerous often weedy plants of several genera of the composite family, including Cirsium, Carduus, and Onopordum, having prickly leaves and floral bracts.
- Any of various other prickly plants, such as Russian thistle.
Origin of thistleMiddle English from Old English thistel ; see steig- in Indo-European roots.