A Skill Tree is a character progression system defined by players allocating points or resources (often Experience or a reward for level-up) within a tree-like structure to unlock and enhance their character's abilities. This mechanism is typically presented as a visual branching diagram, with nodes representing new actions or attributes. A Skill Tree is a common way to give a player agency in deciding the abilities of their character. Skill Trees can be contrasted with Elective Stat Increases, which allow a player to choose a specific stat (a numeric attribute, like Health) to allocate points to increase, although the two sometimes coexist.
A tree may be a web from a single point or multiple long branches. Some systems may have multiple independent Skill Trees. Some systems may offer enough resources to complete an entire Skill Tree, but others may have a hard limit the player can never surpass, forcing them to commit to their character having specific strengths and weaknesses. The ability to reallocate skill points may be freely given or given at a cost.