(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.
Scottish: 1. habitational name, deriving in most cases from the place so called in Annandale, in Dumfriesshire. This is derived from the genitive case of the personal name John + Middle English tone, toun ‘settlement’ (Old English tūn). There are other places in Scotland so called, including the city of Perth, which used to be known as St. John's Toun, and some of these may also be sources of the surname. 2. variant of Johnson (see John), with intrusive -t-.
FOREBEARS As far as can be ascertained, most Scottish bearers of this surname are descendants of a certain John, probably a Norman baron from England, who held lands at Johnstone in Annandale from the Bruce family in the late 12th century. His son Gilbert was the first to take the surname Johnstone and their descendants later held the earldom of Annandale.