The Gospels do not mention the real name of St Thomas, unlike in the case of other apostles . The name Thomas (Koine Greek: Θωμᾶς) given for the apostle in the Gospels is derived from the Aramaic or Syriac: ܬܐܘܡܐ‎ Toma, equivalently from Hebrew Teom, meaning "twin". The equivalent term for twin in Greek, which is also used in the New Testament, is Δίδυμος Didymus.{Courtesy: Wikipedia}

So, if Didymus and Thomas were in fact nick-names, what was the real name of St Thomas the Apostle? What do Catholic traditions have to say on this?