The court ruled in favour of the plaintiff and the defendant had to pay court costs.

wont' that be an appeal?

The wording of the question is too cryptic - however - it appears that the Plaintiffs claim was dismissed due to the plaintiff's lack of prosecution (e.g.: The plaintiff failed to appear in court to press their case -or- the plaintiff withdrew their case- etc).

The Plaintiff.

Plaintiff is the person/legal entity who raises the complaint in a court of law while defendant is the person/legal entity against whom the complaint is raised in the court of law.