# Definition:Stability (Model Theory)/Kappa-Stable Structure

Let $\kappa$ be an infinite cardinal.
Let $\mathcal M$ be an $\mathcal L$-structure.
Let $\operatorname {Th} \left({\mathcal M}\right)$ be the $\mathcal L$-theory of $\mathcal M$.
$\mathcal M$ is $\kappa$-stable if $\operatorname{Th} \left({\mathcal M}\right)$ is $\kappa$-stable.