Definition:Relative Separable Closure

Definition
Let $E/F$ be a field extension.

The (relative) separable closure of $E$ in $F$ is the intermediate field consisting of all separable elements of $E$ over $F$.

Also see

 * Separable Elements Form Field
 * Definition:Separable Closure
 * Decomposition of Field Extension as Separable Extension followed by Purely Inseparable