Dynamic Range is the difference in light levels in an image, between the darkest and the brightest areas.
Cameras with wide dynamic range (WDR) technology can enable the camera to capture details clearly in both the poorly and strongly illuminated areas of the video.
Cameras have problems with underexposed and overexposed images because they can only accurately record the middle area of light between very dark and very bright. Cameras with WDR technology have advanced sensors that can produce a wider range of lighting.
The camera will capture several shots of the scene at different exposure levels. These images are then combined into a composite, with both the brightest and the darkest parts being retained.
For a better understanding, compare the level of detail in the two images below.