Window box Meaning, Definition & Usage

  1. noun a long narrow box for growing plants on a windowsill

WordNet

Definitions
  1. one of the hollows in the sides of a window frame for the weights which counterbalance a lifting sash. also called counterweight channel. (b) a box placed outside a window, on the windowsill, containing soil, in which flowers are grown or displayed as decoration.

Webster 1913