Pro se legal representation comes from Latin pro se, meaning "for oneself" or "on behalf of themselves", which in modern law means to argue on one's own behalf in a legal proceeding as a defendant or plaintiff in civil cases or a defendant in criminal cases.
A defendant is a person or entity accused of a crime in criminal prosecution or a person or entity against whom some type of civil relief is being sought in a civil case.
A legal proceeding is an activity that seeks to invoke the power of a tribunal in order to enforce a law.
A plaintiff is the party who initiates a lawsuit before a court.
Introduction (Representing Yourself in Court) by Indiana Courts
This status is sometimes known as propria persona.
Children and Divorce (Representing Yourself in Court) by Indiana Courts
In England and Wales the comparable status is that of "litigant in person".
England and Wales is a legal jurisdiction covering England and Wales, two of the four countries of the United Kingdom, which form the constitutional successor to the former Kingdom of England and follow a single legal system, known as English law.
In England and Wales, a litigant in person is an individual, company or organisation that has rights of audience and is not represented in a court of England and Wales by a solicitor or barrister.