from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of several plants of the genus Polygonum, with jointed stems and inconspicuous flowers.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of several plants of the genus Polygonum, with jointed stems and inconspicuous flowers
from the GNU version of the Collaborative International Dictionary of English
- n. See knotgrass.
from The Century Dictionary and Cyclopedia
- n. A plant of one of the species of knapweed or knobweed, Centaurea nigra, C. Cyanus, and C. Scabiosa: so called from the knot-like heads.
- n. A plant of the genus Polygonum, which includes the doorweed, the smartweeds and water-pepper, the prince's-feather, etc.; knotgrass or jointweed: so called from the knotty stem.
knot + weed (Wiktionary)