Proper name: ACBARUS. [Abgarus.] (Wikisource | public domain)
Dictionary of Greek and Roman Biography and Mythology (ed. William Smith 1870), Wikisource | public domain
Lewis Short
Acbărus (noun M) : * A title of the Arabian kings, among the Greeks and Romans, Tac. A. 12, 12; also written Abgarus and Abgar, Capit. Anton. 9; Inscr. Orell. no. 921.
Charlton T. Lewis, Charles Short, A Latin Dictionary