Definition of redroot in US English:

redroot

noun

North American
  • 1New Jersey tea, Ceanothus americanus (family Rhamnaceae); (also, with distinguishing word) any of the other shrubs of this genus.

  • 2A swamp plant, Lachnanthes caroliniana (family Haemodoraceae), with hairy yellow flowers, also called paint-root.

  • 3(More fully "redroot pigweed") a kind of amaranth, Amaranthus retroflexus.

Origin

Early 18th century; earliest use found in John Lawson (d. 1711), surveyor.