What is the difference Plaintiff & Defendant ?

The plaintiff is the complaining party, and the defendant is the party who attempts to protect himself from allegations. In most legal systems, the plaintiff bears the burden of proof. The defendant commonly has rights such as to remain silent and to refuse to incriminate herself.

Plaintiff and Defendant are the opposite parties with respect to Civil Laws of any country.

Plaintiff is the one who files a civil suit for his rights to enforce against the defendant from whom he was aggrieved by for his rights. Burden of proof lies on plaintiff to prove the Averment's made in his plaint.

Defendant is the one who is the opposite party and defending the civil suit/case filed against him by the Plaintiff.

So plaintiff and Defendant are related to Civil laws

That the defendant is the person the complainant but the defendant is the person accused by the complainant such as the complainant, he complained in his right.