Acronym for Wide Dynamic Range. This refers to cameras. This is a high end feature. A camera viewing an image with very bright and very dark sections will probably not show any detail in the dark areas as the camera is adjusted to tone down the bright areas. With WDR the camera view will be much improved showing detail in both light and dark areas. This feature also provides better image detail in low light conditions. For e.g. MCCM70 & 1000TVL series are based on WDR technology.