R.

R. is an abbreviation of the Latin word Rex (King) or Regina (Queen).

In jurisprudence, it is used as notation in British or other Commonwealth realm 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 Defendant".

In historiography, r. can be used to designate the ruling period of a person in dynastic power, to distinguish from his or her lifespan.

For example, one may write "Charles V (r. 1519–1556)" instead of "Charles V (1500–1558)" if the writer considers the year of enthronement to be more important information for the reader than the year of birth, or occasionally to emphasise when a ruler abdicated before dying. In addition to rex or regina, r. can also be an abbreviation of ("[he/she] ruled").

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