Let $\mathbb{K}$ be a field. $j: \mathbb{K} \rightarrow L$ a field extension, $x_1 \in L$ And $L_1 = \mathbb{K}[x] := \{P(x_1) \,|\, P \in \mathbb{K}[X]\,\}$, $\Omega$ the algebraic closure of $\mathbb{K}$.
I'm currently reading Antoine Chambert Loire's - A Field guide to Algebra and Loir states:
The restriction to $L_1$ of any $K$-morphism $f: L \rightarrow \Omega$ is a $\mathbb{K}$-homomorphism $f_1$ from $L_1$ to $\Omega$.
I'm asking myself what $K$-morphism means in this context. In the case $K$-morphism $\Leftrightarrow$ $K$-homomorphism the statement is clear to me, otherwise an explanation would be nice.