Verses with the word didymus in the New Testament (3 verses):

John 11:16
Then said Thomas, which is called Didymus, unto his fellowdisciples, Let us also go, that we may die with him.

John 20:24
But Thomas, one of the twelve, called Didymus, was not with them when Jesus came.

John 21:2
There were together Simon Peter, and Thomas called Didymus, and Nathanael of Cana in Galilee, and the sons of Zebedee, and two other of his disciples.