Corner Orientation, abbrevaited CO, the orientation of a cube's corners. There are three possible corner cubie orientations. CO is a sub step in many methods.
For the last layer of the 3x3x3 cube there are three main variations used for the seven cases of CO, one that is named 'pure CO' wich orients the corners without affecting anything else, not even corner permutation, one preserves edge orientation wich is OLL with edges correctly oriented and the last variation orients the corners ignoring edges.
Two corners unoriented
Three corners unoriented
Four corners unoriented