v. & n.
--v.intr.
1. suddenly move or spring back in fear, horror, or disgust.
2 shrink mentally in this way.
3 rebound after an impact.
4 (foll. by on, upon) have an adverse reactive effect on (the originator).
5 (of a gun) be driven backwards by its discharge.
6 retreat under an enemy's attack.
7 Physics (of an atom etc.) move backwards by the conservation of momentum on emission of a particle.
--n. also 1 the act or an instance of recoiling.
2 the sensation of recoiling.
Etymology: ME f. OF reculer (as RE-, L culus buttocks)