Noun
either of two twins who developed from two separate fertilized eggs
Source: WordNetI was not the midwife of the Law School, but its fraternal twin. Norman Lamm
Cassandra was the daughter of King Priam (Priamos) and Queen Hecuba (Hekabe) and the fraternal twin sister of Helenus and a princess of Troy. Source: Internet
Newman was tested for the role of Aron Trask, Dean for the role of Aron's fraternal twin brother Cal. Source: Internet