leaded light 
noun
A window consisting of a lattice of small panes held within strips of lead.He was celebrating the evening mass at about seven o'clock when all the leaded lights in the windows started popping and stones started coming through....
- The buildings display architectural detail both externally and internally with ornate cornices, traditional sash and case windows, leaded lights, timber panelling and original fireplaces.
- Some of the front windows have well-scrubbed leaded lights, while others are covered by faded sheets of old newspaper.