backlight
Light shining from behind something so you can see it.
Backlight is light that comes from behind an object, shining toward the viewer. When you look at your phone or computer screen in a dark room, you're seeing a backlight that illuminates the display from behind, making the words and images visible. Without that hidden layer of light, the screen would be dark and unreadable.
Photographers use backlighting as a technique where the main light source is behind their subject. When you take a picture of someone standing in front of a sunset, they might appear as a dark silhouette because the bright sky behind them creates a backlight effect. Some photographers use this deliberately to create dramatic images, while others add a flash in front to balance the lighting.
The term can also be a verb: when something is backlit, it has light shining through it or from behind it. Stained glass windows in churches are beautiful because they're backlit by sunlight streaming through the colored glass. Theater stages sometimes use backlighting to create mysterious or dramatic effects, with actors appearing outlined in light against a darker foreground.