Coverage, but which?

Ncover measures code coverage. But what exactly is code coverage? Is it statement coverage, line coverage or which one? According to my recognition from the NCoverExplorer, it is at least not method coverage, but I coulndn't find any further hint. In the reports, "sequence points" is meantioned, I assume that these points are the "checkpoints" within the code, but how is this tranferred into coverage?