# What does “oxidized form” and “reduced form” mean?

What does the phrase "oxidized and reduced forms of the reactants" mean?

For some context: The book was talking about half-reactions in a half-cell of a galvanic cell, and it said this,

Sometimes, both oxidized and reduced forms of the reactants in a half-cell are soluble and cannot be used as an electrode.

I am confused as to what the "oxidized and reduced forms of the reactants in a half-cell" might mean because in a half-cell either only oxidation or reduction takes place.

$$\ce{Fe^2+ -> Fe^3+ + e-}$$
Iron takes two forms here, $\ce{Fe^2+}$ and $\ce{Fe^3+}$. $\ce{Fe^3+}$ is the oxidised form, that much is obvious, right? Then, $\ce{Fe^2+}$ is the reduced form.
No $\ce{Fe^3+}$ is actually being reduced to $\ce{Fe^2+}$. However, it is still correct to refer to $\ce{Fe^2+}$ as the "reduced form", since it is the form of iron with the lower oxidation state.