Where does “knobweed” come from?

knobweed (English) comes from English weed, from Middle English weed, from Old English wēod, from Proto-West Germanic *weud — weed (unwanted plant).

knobweed (English): Hyptis capitata, an erect annual lamiaceous shrub

Definitions

  1. Hyptis capitata, an erect annual lamiaceous shrub

Ancestry of “knobweed”, step by step

knobweed traces back through two separate lines of ancestry.

via English weed

StepLanguageWordMeaning
1EnglishweedAny plant regarded as unwanted at the place...
2Middle Englishweed—
3Old Englishwēodweed
4Proto-West Germanic*weudweed (unwanted plant)

via English knob

StepLanguageWordMeaning
1EnglishknobA rounded protuberance, especially one arising...
2Middle Englishknobbeknob; lump, bump
3Middle Low Germanknobbelump, knot; knob; knot in wood
Every word from Proto-West Germanic *weud →
knobweed — Etymology, Origin & Word History | Etymology Explorer