What are the key differences between representing oneself pro se versus pro per in a legal proceeding?

Representing oneself pro se means representing oneself in a legal proceeding without a lawyer, while representing oneself pro per means representing oneself as a party in a legal proceeding without a lawyer. The key difference is in the terminology used in different jurisdictions, with pro se being more commonly used. Both terms refer to the same concept of self-representation in a legal matter.