(N/A) On the basis of the reaction occurring on the surface of the electrode:
In a galvanic cell,the half-cell in which oxidation takes place is called the anode,and the other half-cell in which reduction takes place is called the cathode.
$(b)$ On the basis of electric charge on the electrode:
Positive and negative electrode: More electrons are present in the negative electrode with respect to the positive electrode. $E$.g.,in a galvanic cell,the anode is negative and the cathode is positive.
$(c)$ Classification based on the nature of electrodes:
$(i)$ Active electrode: In a cell,an electrode that shows either an increase or a decrease in its weight is called an active electrode. If an active metal dissolves in the solution during the reaction,its weight is reduced. If,during the reaction,ions from the solution undergo reduction and convert into metal particles that deposit on the electrode,the weight of the metal increases. For example,$Zn$ and $Cu$ metals are active electrodes in a Daniell cell.
$Zn(s) \rightarrow Zn^{2+}(aq) + 2e^{-}$ (Oxidation)
$Cu^{2+}(aq) + 2e^{-} \rightarrow Cu(s)$ (Reduction)
Here,the weight of $Zn$ decreases and the weight of $Cu$ increases.
$(ii)$ Inert electrode: An electrode that provides only its surface for the cell reaction but does not take part in the reaction is termed an inert electrode. $E$.g.,metals like platinum,graphite,etc.,are used in half-cells having either gas or liquid reactants or products. Platinum-$H_2$ gas is an example of an inert electrode.