### Principal

In accounting, the principal is the original amount borrowed or lent on which interest is then paid or given.

The word "principal" is also used in many areas of mathematics to denote one particular object chosen from many possible ones. For example, the principal value of a multivalued function is the canonical value chosen to associate with that functions for convenient or by convention, e.g., 1 for sqrt(1) (even though sqrt(1)=+/-1).