Skills

Skills are most commonly representation of training or knowledge your character has gained through his or her life. In most systems skills are to represent actions in the game that the designers have thought are important or may come up in play. In a stat based system skills often provide a bonus to the stat that "governs" the skill for instance Strength governs climb in DnD. In those systems the skill acts as bonus to the dice roll in addition to the base given by the governing stat.