There is a concept that when a person learns an entire Tractate of Talmud or an entire Order of the Mishna he should make a siyum. This is a festive meal together with a Minyan – a quorum of ten men.
The Babylonian Talmud is split up into many separate Tractates and a festive meal can be made for each and every one when someone learned it from beginning to end. The Mishna is split up into six Orders and the same is true if one finishes a whole Order.
At the siyum, the person making it learns the final bit of the Tractate or Order he studied out loud in front of all the guests.
A siyum is such a festive occasion that the Rabbis describe it as being like a Yom Tov (Festival) for the person who learned the material.
