What is an electrode and a half-cell? Explain their symbolic representation with a suitable example.

(N/A) Electrode: In a galvanic or electrolytic cell,the system formed by placing a metal rod or plate into its own salt solution is known as an electrode,where the flow of current or electrons occurs.
Half-cell: $A$ system consisting of an electrode and the solution in which it is immersed,where either an oxidation or a reduction reaction takes place,is called a half-cell.
Symbolic representation of a half-cell: $A$ vertical line is used to separate the metal and its ion. By convention,for a reduction reaction,the representation is written as $\text{metal ion} \mid \text{metal}$.
For reduction: The symbolic representation of $Zn^{2+} + 2e^{-} \rightarrow Zn$ is $Zn_{(aq)}^{2+} \mid Zn_{(s)}$.
For oxidation: The symbolic representation of $Zn_{(s)} \rightarrow Zn^{2+} + 2e^{-}$ is $Zn_{(s)} \mid Zn_{(aq)}^{2+}$.
If the reactant or product is a gas or liquid,platinum $(Pt)$ is typically used as an inert electrode. Examples:
$(i)$ Hydrogen electrode:
Anode (Oxidation): $Pt_{(s)} \mid H_{2(g)} \ (1 \ \text{bar}) \mid H_{(aq)}^{+}$
Cathode (Reduction): $H_{(aq)}^{+} \mid H_{2(g)} \ (1 \ \text{bar}) \mid Pt_{(s)}$
$(ii)$ Bromine electrode:
Cathode (Reduction): $Pt_{(s)} \mid Br_{2(aq)} \mid Br_{(aq)}^{-}$
Anode (Oxidation): $Br_{(aq)}^{-} \mid Br_{2(aq)} \mid Pt_{(s)}$