Cassie \c(as)-sie\ as a girl's name is pronounced KASS-ee. It is of English origin. Short form of Cassandra and Katherine frequently used as an independent name. See also Kassie. Cassie has 11 variant forms: Cassee, Cassey, Cassi, Cassy, Casy, Kasse, Kassey, Kassi, Kassie, Kassy and Kasy. For more information, see also related names Casey, Acacia, Cass and Catherine. Baby names that sound like Cassie are Caysie, Cassye, Casse, Casie, Caisie and Cassia. View a list of the 8 names that reference Cassie.