REX
n. uncountablen. the reigning king. It is used in legal cases or official documents to show that the king is the person bringing a charge against someone.
n. the reigning king, used especially in legal citations and formal titles to represent the state or the Crown. It is the masculine equivalent of Regina.
The court case was listed as Rex v. Smith.
In many Commonwealth countries, legal proceedings are brought in the name of Rex when a king is on the throne.
The transition from Regina to Rex in legal documentation reflects the change in the gender of the monarch, though the underlying authority of the Crown remains constant.
Used in legal contexts, typically abbreviated as 'R' in case citations (e.g., R v. Brown). It is always capitalized when referring to the monarch.