The Stacks project

Definition 59.56.1. Let $S$ be a scheme. Let $\overline{s}$ be a geometric point lying over the point $s$ of $S$. Let $\kappa (s) \subset \kappa (s)^{sep} \subset \kappa (\overline{s})$ denote the separable algebraic closure of $\kappa (s)$ in the algebraically closed field $\kappa (\overline{s})$.

1. In this situation the absolute Galois group of $\kappa (s)$ is $\text{Gal}(\kappa (s)^{sep}/\kappa (s))$. It is sometimes denoted $\text{Gal}_{\kappa (s)}$.

2. The geometric point $\overline{s}$ is called algebraic if $\kappa (s) \subset \kappa (\overline{s})$ is an algebraic closure of $\kappa (s)$.