\begin{definition}[Definition:Separable Extension]
Let $K$ be a field.
Let $L/K$ be an algebraic field extension.
Then $L/K$ is a '''separable extension''' {{iff}} every $\alpha\in L$ is separable over $K$.
That is:
:For every $\alpha \in L$, its minimal polynomial over $K$ is separable.
\end{definition}