naming clarification

book/02_maxwell_eq.md

@@ -7,7 +7,7 @@ B &= \mu H
 \end{align}
 $$
 
-Where $\epsilon$ is the electric permittivity and $\mu$ is the magnetic permeability.
+Where $\epsilon$ is the electric permittivity and $\mu$ is the magnetic permeability. In prose I will sometimes refer to both $D$ and $E$ as the electic field and $B$ and $H$ as the magnetic field so don't get tripped up on that. Technically $D$ is the electric displacement field and $B$ is magnetic flux density.
 
 There are two ways to look at Maxwell's Equations: derivative form and integral form. Both can be useful however I think the derivative form tends to be a more concise way to look at things so we'll start with that.
 Don't worry about understanding all of these yet, we'll go through them one at a time.