Billy \b(il)-ly\ as a girl's name (also used as boy's name Billy), is a variant of Billie (Old English) and Wilhelmina (Old German), and the meaning of Billy is "will helmet, protection".

The baby name Billy sounds like Bailly, Billye, Billi, Billa and Billey. Other similar baby names are Milly, Cilly, Gilly, Hilly, Jilly, Lilly, Tilly and Willy.