| great knapweed | (n) tall European perennial having purple flower heads, Syn. greater knapweed, Centaurea scabiosa |
| jersey knapweed | (n) a variety of knapweed |
| knapweed | (n) any of various plants of the genus Centaurea having purple thistlelike flowers |
| lesser knapweed | (n) a weedy perennial with tough wiry stems and purple flowers; native to Europe but widely naturalized, Syn. Centaurea nigra, black knapweed, hardheads |
| slender knapweed | (n) a variety of knapweed |
| Knapweed | n. (Bot.) The black centaury (Centaurea nigra); -- so called from the knoblike heads of flowers. Called also |