Cedilla

Ce‐dil″la (sē̍‐dĭl″lȧ), n. [Sp. cedilla, cf. F. cédille; dim. of zeta, the Gr. name of the letter z, because this letter was formerly written after the c, to give it the sound of s.] A mark placed under the letter c, to show that it is to be sounded like s, as in façade.