noun knap·weed \ˈnap-ˌwēd\

Definition of knapweed

  1. :  any of various weedy centaureas; especially :  a widely naturalized European perennial (Centaurea nigra) with tough wiry stems and knobby heads of purple flowers

Origin and Etymology of knapweed

Middle English knopwed, from knop knop + wed weed

First Known Use: 15th century

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