What is a lawsuit?
A lawsuit is a civil legal action brought in a court. Typically one party is suing another party for money or other property. (The term party can include individuals, businesses and government agencies.)
The person suing is typically called the plaintiff; the person being sued is the defendant.
Lawsuits sometimes also involve an action to enjoin - a legal term than means restrain or stop a party from doing something, such as picketing or trespassing on your property or disclosing confidential information.
A lawsuit is one way that people and companies can resolve disputes arising out of an infinite variety of factual circumstances.