Sister Jeuna is an instructor at the Catholic women's college to whom Sister Justinian snarkily refers to as "Sister Visual Aids" (Saint Fidgeta and Other Parodies, 72).
Jeuna may be a derivative of jeûner: to fast; to go without food.
From the derogatory name given to her one may deduce both her occupation (perhaps audiovisual education) and popularity with others (perhaps disdained).
|7. Easter Address to the Faculty by the President of a Catholic Women's College|