RABBONI (from Heb. רַבָּן or דַבּוֹן) is another form of ‘Rabbi,’ but was considered a higher and more honourable title. Hence possibly its preference by the blind man (Mark 10:51) in his natural anxiety to address Jesus with the title of greatest courtesy and respect that he knew. The word occurs only twice in the Gospels, viz. Mark 10:51 (Revised Version NT 1881, OT 1885 following the reading of most authorities), and John 20:16 (ῥαββουνί, Textus Receptus ; ῥαββουνεί, WH [Note: H Westcott and Hort’s text.] ). In the latter passage it is explained as a synonym for διδάσκαλος.
Dugald Clark.