“What does capitulum mean?”
Since the 8th century, monks, after the hour before, gathered to listen to the reading of a “chapter” (capitulum) of the Rule of St. Benedict. Gradually, the gathering itself was called “the chapter,” and the place where it was held: “the chapter house.” There were two types of “chapters” in monasteries:
1) The first was for Consultation: the Abbot would seek the advice of the community on some matter.
2) The second was for Formation: the Abbot would comment on the passage of the Rule just read.
The “General Chapter” was established by the Cistercians in 1195. All abbots met annually in Cîteaux (France).
In November 1215, the Fourth Lateran Council, which Francis attended, decided that religious Orders should celebrate chapters periodically as a means of reforming religious life, following the example of the Cistercians. Francis and his early followers began regular meetings for mutual encouragement and support, admonition and correction as they began their life together. Each of these would later be called capitulum (“chapter”) following the example of the Cistercians.
Thanks to https://ofmcapgen2021.org/it/che-cose-un-capitolo/ for the information