Leadlight is decorative panels or windows made with small sections of glass housed in lead. Stained glass windows, if they use lead between the sections, are also known as leadlight, but traditionally are thought to be larger pieces in churches or cathedrals rather than smaller objects where the term headlight is more appropriate.
In recent times the distinction between the two phrases is blurry but stained glass windows are thought to be synonymous with religious or pastoral scenes whereas headlight windows or panels are more likely to be decorative and patterned with no story or theme.
Leadlight was popular and commonly found in homes built between 1860 and 1930 and can indicate the age of a building, however take care to check for artificial headlight which is a piece of standard glass with the decorative lead placed on top of the glass and then a film or stain placed on the plain glass in between.
Original leadlight pieces in good condition can fetch excellent prices at auctions, and repairing brittle headlight can be tricky. A skilled leadlighter will be needed to repair!