Rabboni

Jesus said to her, "Mary!" She turned and said to Him, "Rabboni!" (which is to say, Teacher).
John 20:16

 The difference between a Rabbi and a Rabboni is just a matter of degrees. In American universities there are three levels of academic achievement: Bachelors, Masters, and Doctorate. In the same way, teachers of the Torah advanced in their scholarship.

The first level for a Jewish sage was that of a Rab (literally Master). The origin traces back to the development of synagogues during the Babylonian captivity. The Rab was the ruler of the synagogue and was designated by the congregation by the laying on of hands.

The middle level was that of a Rabbi and developed after the return of the exiles to Jerusalem. The title means “my master” and referred to a master teacher who would attract disciples to him. They would serve their Rabbi and he would both teach and provide for them.

The highest level was Rabboni, meaning “my great Master.”  Only the most respected sages that would see their disciples for a number of spiritual generations were honored this way.

Mary Magdalene called her Lord "Rabboni". As a woman of questionable reputation, she was not known for her scholarship. What she was known for was that she was a sinner who was forgiven much. She bestowed the high honor on the Risen Lord.

The only other mention of the title Rabboni was by the blind beggar, Bartimaeus. Again, he was not a direct disciple of Jesus and being blind, he couldn't read, much less study the Hebrew scriptures. However, he had great spiritual insight.

When Jesus was passing through Jericho, the blind man called out the Messianic Title, “Son of David”, to Him. When the crowd would hush him up, he called out even louder. When Christ asked him what he wanted, Bartimaeus replied, “Rabboni,” (My Great Master), “That I may receive my sight” (Mark 10:51).