If the defendant fails to enter an appearance, the plaintiff can apply to court for judgement in default of appearance, this can also be referred to as 'Judgement in default'.
This means that because the defendant has failed to acknowledge the proceedings and indicate that they intend to defend them, the plaintiff may obtain a judgement from the court against the defendant without the need for a trial.
If the defendant does enter an appearance but fails to deliver a defence the plaintiff may obtain a judgement in default from the court against the defendant.