as zac said, different lens take filters of different sizes. a 62mm filter is a filter with a diameter of 62mm. for example, a Nikkor 80-200mm f2.8 lens takes a filer of 77mm(if i recall correctly), a Nikkor 50mm f1.8mm takes a 52mm filter.
Btw, some filter sizes are more common than the rest, like 52mm, 67mm, 77mm. This is because many lenses accept filters of these sizes. Meaning you can interchange your filters.