# Why are faithful actions called faithful and who first called them faithful?

This is a cross post from MSE

I want to know why are faithful actions called faithful and who first called them faithful?

Definition: An action $$G$$ on $$X$$ is faithful when $${g_1 \neq g_2 \Rightarrow g_1 x \neq g_2 x}$$ for some $${x \in X}$$ (different elements of $$G$$ act differently at some point).

• Has been answered on Mathoverflow. – C.F.G Sep 18 at 9:12