Definition of water-rocket in US English:

water-rocket

noun

rare
  • Any of various aquatic or semiaquatic plants of the genus Rorippa (family Brassicaceae (Cruciferae)), as creeping yellowcress, R. sylvestris, and common yellowcress, R. palustris.

noun

  • 1A firework designed to be discharged in the water. Now historical.

  • 2A model rocket consisting of a hollow vessel that is partially filled with water and launched by pumping air (or some other gas) into it until the resulting pressure forces the water out of a nozzle, propelling the rocket upwards.

Origin

Early 17th century. From water + rocket, probably after post-classical Latin eruca aquatica<br>mid 17th century; earliest use found in John Bate (fl. 1626–1635), writer on mechanics. From water + rocket.

Pronunciation

water-rocket

/ˈwɔːtəˌrɒkɪt/