Jan m, f
1 (m.); pronounced /jan/ Dutch, Low German, Scandinavian, Polish, and Czech form of JOHN (SEE John).
2 (m.); pronounced /dzæn/) English: a revival of Middle English Jan, a byform of JOHN (SEE John). The forms Johan and Jehan are found in Old French and Early Middle English, but in Middle English the name was generally shortened to a monosyllable, spelled variously Jon, John, and Jan. It has sometimes been suggested that the latter is an importation from Low German or Dutch, but this seems unnecessary.
3 (f.); pronounced /dzæn/) English: an increasingly popular female given name, formed either as an independent feminine form of JOHN (SEE John) (alongside JOAN (SEE Joan), JEAN (SEE Jean), JANE (SEE Jane), etc.) or as a shortened form of names beginning with Jan-, principally JANET (SEE Janet) and JANICE (SEE Janice).
First names dictionary. 2012.