White balance is an adjustment to correct and neutralise colors captured with different light sources. The color of light can vary considerably depending on the time of day and whether you’re shooting in natural light or under artificial light.
Color cast
A color cast is where the colors in an image seem to show a general shift, for example the yellow-orange color cast you typically get with pictures taken in domestic artificial lighting, or the bluish skintones of portraits taken in shade under a blue sky. Color casts can often be corrected digitally, or prevented by choose a better white balance setting to take the picture.