What is "primicerius"

The Latin term primicerius, hellenized as primikērios , was a title applied in the later Roman Empire and the Byzantine Empire to the heads of administrative departments, and also used by the Church to denote the heads of various colleges.

Etymologically the term derives from primus in cera, which is to say in tabula cerata, the first name in a list of a class of officials, which was usually inscribed on a waxed tablet.