The form found in Western names originates from the Hebrew ירדן Yarden, relating to the Jordan River in West Asia.
[1] According to the New Testament of the Bible, John the Baptist baptised Jesus Christ in the Jordan,[2] and during the Crusades, crusaders and pilgrims would bring back some of the river water in containers to use in the baptism of their own children in Europe and Britain.
[1] Jordanes, a 6th-century Gothic historian, may have popularised the name as well.
[3] The Greek form is Ἰορδάνης (Iordanes),[2] in Arabic it is Al-Urdunn, in Latin Jordanus, in Italian Giordano, in Spanish Jordán, in Portuguese Jordão, in German Jordan, in Dutch Jordaan, in French Jourdain, in Irish Iordáin or Riordan, in Russian Йордан (Yordan), in Romanian Iordan, in Bulgarian Йордан (Yordan), in Polish Jordan, and in Catalan Jordà.
The English form of the name appears to have died out after medieval times, but started to be used again the 19th century, becoming especially popular in the U.S. and some other countries in the latter half of the 20th century.