Canada thistle

noun

1. an Old World plant, Cirsium arvense, having small purple or white flower heads, now a troublesome weed in North America.

Canada thistle

noun

1. See creeping thistle
   the US and Canadian name for creeping thistle

Word History and Origins

Origin of Canada thistle¹

An Americanism dating back to 1790–1800

Example Sentences

Little bits of Canada-thistle root half an inch long may send forth buds, and each bud grow to be an independent plant.

From Project Gutenberg