Rabbinate refers to the office or function of a rabbi.
In Hebrew we say, literally, “He sat on the rabbinate chair”.
The autonomous self-governing Jewish body of the communities, or as Friedlander translates Dubnov’s Hebrew - the “Kahal board” – included members who were not rabbis. They dealt with administration and material issues.
They were elected annually during the intermediate days of Passover. Between 5-9 electors were appointed by lot from among the members of all synagogues, and they, in turn, after taking a solemn oath, chose the Kahal elders.
The elders were divided into groups. Two of these, the rashim and tuvim _the "heads" and "optimates"– stood at the head of the administration, and were in charge of the general affairs of the community. They were followed by the dayyanim [religious judges] and the gabbaim [see my glossary]. The rabbi had unrestricted authority in religious affairs, but the AB”D, depended on the Kahal board to be appointed to his post [to “the rabbinate”]. The combined over-all governing body – the va’ad , often rendered Council - was made up of several leading rabbis and of one delegate for each of the principal Kahals selected from among their elders. In the Ve’adim –conventions, meetings of the Councils– the rabbis not always participated and were invited for Religious disputes.