Many effects impose a condition, a temporary state that alters the recipient’s capabilities. The following conditions are defined in the rules glossary:
The definition of a condition specifies what happens to its recipient while affected by it, and some conditions apply other conditions.
A condition lasts either for a duration specified by the effect that imposed the condition or until the condition is countered (the Prone condition is countered by standing up, for example).
If multiple effects impose the same condition on you, each instance of the condition has its own duration, but the condition’s effects don’t get worse. Either you have a condition or you don’t. The Exhaustion condition is an exception; its effects get worse if you have the condition and receive it again.