From BiblePortal Wikipedia

Hastings' Dictionary of the New Testament [1]

DIDYMUS. —The alternative name of the Apostle Thomas, given in three passages in the Fourth Gospel ( John 11:15;  John 20:24;  John 21:2 Θωμᾶς ὁ λεγόμενος Δίδυμος). The adj. δίδυμος is regular Greek from Homer onwards, with the meaning ‘twofold’; hence δίδυμος as subs. = ‘a twin.’ Δίδυμος is the translation, as Θωμᾶς is the transliteration, of תִּאם = תֹּאמָא ‘a twin.’

Why St. John calls special attention to this name is not clear. Westcott suggests that Thomas may have been familiarly known in Asia Minor among the Gentile Christians as Didymus .  John 4:25 (‘Messiah … which is called Christ’) shows that Thomas was not called Didymus as an additional name. See Thomas.

E. H. Titchmarsh.

Smith's Bible Dictionary [2]

Did'ymus. (The Twin). A surname of the apostle Thomas.  John 11:16;  John 20:24;  John 21:2. See Thomas .

Fausset's Bible Dictionary [3]

Greek: "twin" equates to Hebrew: "Thomas". Compare  John 11:16;  John 20:24;  John 21:2.

Easton's Bible Dictionary [4]

 John 11:16 20:24 21:2

Holman Bible Dictionary [5]

 John 11:16Thomas

Hastings' Dictionary of the Bible [6]

DIDYMUS . See Thomas.

Morrish Bible Dictionary [7]


Cyclopedia of Biblical, Theological and Ecclesiastical Literature [8]

( Δίδυμος , the Twin ), a surname ( John 11:16) of the apostle THOMAS (See Thomas) (q.v.).

International Standard Bible Encyclopedia [9]

did´i - mus ( Δίδυμος , Dı́dumos , i.e. "twin"): The surname of Thomas (which see).

Kitto's Popular Cyclopedia of Biblial Literature [10]

Did´ymus (a twin), a surname of the Apostle Thomas, denoting that he was a twin; and if translated, he would be called 'Thomas the Twin' [THOMAS].

The Nuttall Encyclopedia [11]

A surname of St. Thomas; also the name of a grammarian of Alexandria, a contemporary of Cicero, and who wrote commentaries on Homer.