Definition:Congruence (Number Theory)/Residue

Definition
Let $z \in \R$. Let $a \in \R$.

A residue of $a$ modulo $z$ is another word meaning remainder, and is any number congruent to $a$ modulo $z$.

Also defined as
Some sources define the residue to be the smallest number congruent to $a$ modulo $z$.

Also see

 * Definition:Least Positive Residue