Sister Coroda is a tenured instructor in the chemistry department at the Catholic women's college. She has recently taken up the entire third floor of the new science hall with her office, living area, and television lounge. Sister Justinian informs the college staff that Coroda's fifty years of service "gives her the ius primae usufructus" on college equipment and that she uses it to record television programs for use in homes "for the mentally retarded" (Saint Fidgeta and Other Parodies, 72).
While it’s possible it could be used as a real name, coroda seems little more than an echo for corrode.
The sister's name is similar to Sister Correda, one of the teachers at Johnny Dixon's school. It is unknown whether Bellairs had a teacher with a similarly-sounding name since it appears twice in his writings.