“Socius criminis” is a Latin term used in law that translates to “partner in crime” or “accomplice” in English. It refers to a person who assists, encourages, abets, or aids another person in committing a crime. In legal contexts, the term is often used to describe someone who participates in a criminal act together with the main perpetrator, either by actively taking part in the crime or by helping to plan or facilitate it in some way.