"Mandamus" is the first person plural present indicative active form of the Latin word meaning to command. It is most likely the result of combining the Latin word for "hand", manus, with the Latin word "to give", do. Some readers may be familiar with the religious holiday with the unusual name of Maundy Thursday. The word "maundy" is ultimately derived from the same Latin word, having worked its way through Old French. "Maundy" refers to Jesus' commandment to his disciples as reported in John 13:34. The relationship is of the words is clear in the Latin translation of the text (the original was written in Greek): "Mandatum novum do vobis . . ." (I give a new command to you). Mandatum is the singular neuter perfect passive participle form of the verb. The word "mandate" is derived from this form of the verb.
Here in California, the writ of mandamus may be referred to as a "writ of mandate". Cal. Code Civ. Proc. § 1084. In general, California recognizes two types of mandate proceedings - "ordinary mandate" and "administrative mandate". Both types of writs are used to correct administrative agency action, but the types of actions that may be corrected differ. Section 1085 of the Code of Civil Procedure governs ordinary mandate and it is used to compel agencies to perform ministerial acts. It is also available to compel the admission of a person to the use and enjoyment of a right or office to which the person is entitled, and from which the person is unlawfully precluded. A court may issue a writ of ordinary mandate against a corporation in the same circumstances. Administrative mandate is governed by Section 1094.5 and is used to review the validity of any final administrative order or decision made as the result of a proceeding in which by law a hearing is required to be given.