Definition:Signature (Logic)

Definition
Let $\mathcal L$ be a formal language.

A choice of vocabulary for $\mathcal L$ is called a signature for $\mathcal L$.

Also known as
Some sources refer to a signature as a lexicon.

Others call it a language, particularly in the field of model theory.

However, this is easy to conflate with the generic formal language, and therefore discouraged on.

Also see

 * Definition:Vocabulary