Definition of red catchfly in US English:

red catchfly

noun

rare
  • A Eurasian campion of rocks and crags, Lychnis viscaria, which has spikes of bright pink flowers and often dark sticky bands around the stem beneath each node; compare red German catchfly; also called sticky catchfly.

Origin

Late 18th century; earliest use found in John Lightfoot (1735–1788), Church of England clergyman and naturalist.