Perks

 are special abilities which unlocked while levelling up. One perk can be chosen per level. There are a number of perks available for each of the eighteen skills. If a perk option is not used during a levelling up, it can be used on subsequent levels, or at any time in between by accessing the Level Up menu. In the original game, perks cannot be changed or undone once selected.

The Elder Scrolls V: Dawnguard
Eleven additional perks are available with the Dawnguard plug-in.

The Elder Scrolls V: Dragonborn
After installing the Dragonborn DLC and completing the main quest, perks may be undone and redistributed at the cost of one dragon soul per skill tree.

Talente