A common theme introduced in Dragonball Z is the 'Powerlevel' which represents an individual's combat strength. The fighter with the highest powerlevel typically holds an advantage in combat. Powerlevel (PL) is similar to Experience Points earned in other types of games as it is a general representation of a character's combat strength.

Example: Powerlevel<Base/Current>

Base PL determines what equipment a character can use and which skills it can learn. Current PL can be increased with various transformations.

While Powerlevel is generally a reliable guide, it is important to note that equipment, stats, and skills have a major impact in combat, particularly between players. 

Powerlevel is generally trained during combat with mobs and other players. Early on, gravtraining can increase a low level character's stats and PL.

While the term Powerlevel is typically used interchangeably, certain races have others displayed:
Androids have a Techlevel.
Fierian demons have a Heatlevel.
Wizards have Potential.