Cross-class skill

A cross-class skill is a skill which is not a class skill for one of your classes. The maximum rank for a cross-class skill is equal to (3 + character level) / 2 (rounded down).

When leveling up, a skill point will give only 0.5 rank if put in a cross-class skill for the class you are leveling in. If it is a class skill for one of your other classes, the cap is still the one of a class skill, i.e. 3 + character level.