rupert's drop Meaning, Definition & Usage

Ru"pert's drop`
Definitions
  1. A kind of glass drop with a long tail, made by dropping melted glass into water. It is remarkable for bursting into fragments when the surface is scratched or the tail broken; -- so called from Prince Rupert, nephew of Charles I., by whom they were first brought to England. Called also Rupert's ball, and glass tear.

Webster 1913