A Stained glass is a decorative composition that derives its effect from the translucency of its support. Let's not try to be more specific: the definition would risk leaving out the oldest, as well as the most recent manifestations of an art that has not yet said its last word.
Focus on its decorative role that plays with light.
If the religious vocation is often attached to illuminating religious monuments, try nevertheless to place them in innovative contexts.
Take care of he colors, the environment and the artistic aspect.
And vote on these elements.