Latinised form of the Greek name Θαδδαιος (Thaddaios) of uncertain meaning. Theories include:
1) Greek spelling of an Aramaic version of a short form of a Greek name:
2) Greek name meaning: 'praise' 
3) Greek form of an Aramaic name meaning 'brave' 
4) Greek form of the Aramaic name Thaddai meaning 'heart' 
|Genitive:||Thaddeus' / Thaddeus|
|Female ♀||Male ♂|
|#: count of main first name only|
|&: count of both main and additional first names|
| Name counts are approximate as statistics normally is not published
for names given to less than 3 or 5 persons per country.
No recent statistics trend found in databases for Thaddeus.