# Definition:Predicate Symbol

## Definition

Let $\mathcal L$ be a formal language (for example, the language of predicate logic $\mathcal L_1$).

A predicate symbol is a letter of $\mathcal L$ used to describe a predicate or a relation.

The name predicate symbol is a gesture to the reader to make clear what such a symbol should (intuitively) represent in the formal language $\mathcal L$.

## Also known as

A predicate symbol is also often called a relation symbol.

Some sources refer to it as a predicate letter.