Final answer:
In the context of a legal dispute over unpaid rent, the individual bringing the case, George, is called the plaintiff, while Martin, who is accused of non-payment, is termed the defendant.
Step-by-step explanation:
When George took Martin to court for non-payment of rent, the judge referred to George as the plaintiff. In a rental dispute such as this, the tenant (Martin) who is being accused of not paying rent would typically be referred to as the defendant.
The terms 'plaintiff' and 'defendant' are classifications used in legal proceedings to denote the party bringing the lawsuit and the party against whom the lawsuit is brought, respectively.