R.

R. is an abbreviation of the Latin word "Rex" (King) or "Regina" (Queen) and is used as notation in British criminal prosecutions to mean "the Crown" or "the State", which is represented by the current monarch.

It is often seen written as "R. v Defendant" which would be read as "the Crown against the Defendant".

In jurisdictions that are republics, there is no Monarch and no one person embodies the state, so the prosecuting party is not any individual but rather either the State in and of itself, or (in some locations) the state "on the behalf of" the people it governs. An example of the former would be federal criminal cases in the United States (such as, for instance, the murder of persons in a building owned or operated by the United States government), which being prosecuted by the United States federal government would be termed "United States v Defendant". On the other hand, most U.S. states, when prosecuting an offense, typically couch their case in terms of representing the people of the state, so if John Doe robbed a bank in Detroit, the case would be referred to as "the People of the State of Michigan v John Doe".