Regius professor n 1: holder of a British professorship created by a royal patron
Regius \Re"gi*us\ (r?l"?*?s), a. [L. regius, from rex, regis, a king.] Of or pertaining to a king; royal. [1913 Webster] {Regius professor}, an incumbent of a professorship founded by royal bounty, as in an English university. [1913 Webster]