A cedilla 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", and the word "cedilla" is the diminutive of the old Spanish name for this letter, ceda. An obsolete spelling of cedilla is cerilla.(1) For cedilla being the diminutive of ceda, see http://buscon.rae.es/draeI/SrvltGUIBusUsual?TIPO_HTML=2&LEMA=cedilla definition of cedilla, Diccionario de la lengua española, 22nd edition, Real Academia Española.