Answer found in Wikipedia.
A cedilla (pronounced /sɪˈdɪlə/) is a hook (¸) added under certain consonant letters as a diacritical mark to modify their pronunciation. The tail originated as the bottom half of a miniature cursive "z". The word "cedilla" is the diminutive of the old Spanish name for this letter, ceda, where it was first used. Modern Spanish, however, no longer uses this diacritic. An obsolete spelling of cedilla is cerilla.[1]