There are multiple origins, definition and meanings for the name Thomas:
1. Aramaic [teoma] and Hebrew name (תְאוֹם) [teom] meaning - "twin". Thomas is the most popular male name in Germany.
2. Ancient Greek name, comes from the word (tόμος) [tόmos] meaning - "piece, slice" or from (τομός) [tomόs] - "cutting, sharp, acute; harsh, resolute".
Thomas the Apostle, also called Doubting Thomas or Didymus, was one of the Twelve Apostles of Jesus [other apostles: Andrew brother of the Apostle Peter (the fisherman from Bethsaida, a disciple of John the Baptist), Peter (or Simon son of John, also called Cephas), John the Evangelist, James son of Zebedee, Philip of Bethsaida, Bartholomew aka Nathaniel, Matthew the tax collector (also Levi Alpheus), James the son, Thaddeus son of Alpheus (also known as Jacob or Judah Levi), Simon the Zealot (also Simon the Zealot) and Judas Iscariot (who betrayed Jesus)]. He is best known for disbelieving Jesus' resurrection when first told of it, then proclaiming "My Lord and my God" on seeing Jesus in John. He was perhaps the only Apostle who went outside the Roman Empire to preach the Gospel.