(male) Probably the most successful of all the Old French names of Germanic origin that were introduced to England by the Normans. It is derived from Germanic wil ‘will, desire’ + helm ‘helmet, protection’. The fact that it was borne by the Conqueror himself does not seem to have inhibited its favour with the ‘conquered’ population: in the first century after the Conquest it was the commonest male name of all, and not only among the Normans. In the later Middle Ages it was overtaken by John, but continued to run second to that name until the 20th century, when the picture became more fragmented.
Short forms: Will, Bill.
Pet forms: Willy, Willie, Billy.
Cognates: Irish: Uilliam. Scottish Gaelic: Uilleam. Welsh: Gwilym. German: Wilhelm. Dutch: Willem. Scandinavian: Vilhelm. French: Guillaume. Spanish: Guilermo. Catalan: Guillem. Portuguese: Guilherme. Italian: Guglielmo. Czech: Vilém. Slovenian: Viljem. Hungarian: Vilmos. Lithuanian: Vilhelmas. Latvian: Vilhelms.
English, Scottish, and northern Irish: patronymic from Jack 1. As an American surname this has absorbed other patronymics beginning with J- in various European languages.
FOREBEARS This extremely common British name was brought over by numerous different bearers in the 17th and 18th centuries. One forebear was the father and namesake of the seventh U.S. president, Andrew Jackson, who migrated to SC from Carrickfergus in the north of Ireland in 1765. The Confederate General Thomas ‘Stonewall’ Jackson came from VA, where his great-grandfather John, likewise of Scotch–Irish stock, had settled after emigrating to America in 1748.