The albedo of an object is the amount of incident radiation that is reflected back into space by that object. It is the total amount of radiation reflected () into space by an object divided by the total amount of radiation that hits the object ().
The more light reflected, the higher the albedo. An object with a higher albedo will appear brighter than an object with low albedo, all other things (size, incident radiation, distance to the object) being equal. This is because the higher albedo object is reflecting more of the light back into space for us to see. A perfect white reflector would have an albedo of 1. A perfect black absorber would have an albedo of 0.
Albedo of some common objects