Definition of blue rocket in English:

blue rocket

noun

  • Any of various plants having an upright blue or bluish inflorescence; especially monkshood, Aconitum napellus, and (more fully "blue rocket larkspur") the larkspur Consolida regalis.

Origin

Late 18th century; earliest use found in John Abercrombie (1726–1806), horticulturist and writer.