noun
colored glass
Refers to glass that has been colored, often used in art, architecture, or decorative items.
教会の色ガラスの窓がとても美しい。
The church's stained glass windows are very beautiful.
ガラス is plain glass; 色ガラス specifically means colored or stained glass.
Compound of 色 (iro, 'color') and ガラス (garasu, 'glass').