What does photography backlight mean?

Backlight means that the light comes from behind the subject, and most people shoot with positive light or positive light, that is, the light comes from behind or around the photographer. These can be classified as smooth light, and the exposure of the photographed things will be relatively uniform, and there will be no excessive contrast and contrast, but the effect of positive light will be relatively dull, which will easily lead to inaccurate metering because the contrast is too large. If you don't use the technology of fill light, either the subject is exposed normally and the background is overexposed, or the other way around, but if you can make good use of the backlight, you can still do it.