What does 28 to 80mm on a camera lens mean?

It relates to the focal length of a zoom lens - in this case 28 mm being wide angle (but noit as wide as a fish eye lens) through to medium telephoto - 80mm or thereabouts is used by 35mm SLR photographers to capture portraits. A standard lens on 35mm SLR is around the 50mm mark. Note that I have used 35mm SLR as the reference - it varies deopending on the format - I believe digital SLRs are different also.