(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, French, German, Dutch, Danish, and South Indian: from the medieval personal name, of Biblical origin, from Aramaic t’ōm’a, a byname meaning ‘twin’. It was borne by one of the disciples of Christ, best known for his scepticism about Christ's resurrection (John 20:24–29). The th- spelling is organic, the initial letter of the name in the Greek New Testament being a theta. The English pronunciation as t rather than th- is the result of French influence from an early date. In Britain the surname is widely distributed throughout the country, but especially common in Wales and Cornwall. The Ukrainian form is Choma. It is found as a personal name among Christians in India, and in the U.S. is used as a family name among families from southern India.