noun
window grate; window grating
A lattice or grid of bars fixed over a window for security or decoration. Often seen on ground-floor windows in Japan.
See also: 格子
一階の窓には面格子が付いている。
The ground-floor windows have grates on them.
防犯のために面格子を設置した。
We installed window grates for crime prevention.
Compound of 面 (めん, 'surface') and 格子 (こうし, 'lattice'), literally 'surface lattice'. The exact historical derivation is uncertain, but the word transparently describes a lattice fixed to a window surface.