English form, used in the Authorized Version of the Bible (alongside the Latin form Timotheus), of the Greek name Timotheos, from timē ‘honour’ + theos ‘god’. This was the name of a companion of St Paul; according to tradition, he was stoned to death for denouncing the worship of Diana. It was not used in England before the Reformation but has been in steady use since the 18th century.
Irish: reduced Anglicized form of Gaelic Ó Loingsigh ‘descendant of Loingseach’, a personal name meaning ‘mariner’ (from long ‘ship’). This is now a common surname in Ireland but of different local origins, for example chieftain families in counties Antrim and Tipperary, while in Ulster and Connacht there were families called Ó Loingseacháin who later shortened their name to Ó Loingsigh and also Anglicized it as Lynch.