masc. proper name, from Latin Caecilius (fem. Caecilia), name of a Roman gens, from caecus "blind" (see caecum).
Cicely
fem. proper name, an alteration or nativization of Cecilia. The popular plant name (late 16c.) is a corruption (by influence of the proper name) of Latin seselis, from Greek seselis, a foreign word, perhaps from Egyptian.
Sheila
fem. proper name, Irish equivalent of Celia, shortened form of Cecilia, the fem. form of Cecil. A standard type of an Irish women's name since 1828, hence later slang sense of "girlfriend, young woman." An 1839 source has shalers as a "country phrase" for "girls," and this may represent the casual pronunciation of the name.