double glazing; double-glazed window glass
Refers to the glass itself or the glazing system; often used in contexts of insulation or soundproofing.
This apartment is quiet thanks to the double-glazed windows.
Installing double glazing reduces heating costs.
複層ガラス is a more technical term for multi-layered glass, often used in architectural specifications.
Compound of 二重 (double) + 窓 (window) + ガラス (glass). A straightforward modern term.