Keith is of Scottish origin, derived from the Gaelic word 'Caoit' which means 'wide'. It was originally used as a surname before becoming a popular given name in the 19th century. Keith is often associated with the English form of the name, Caius, meaning 'rejoice'. Notable individuals with this name include Keith Richards, the influential guitarist and founder of The Rolling Stones, and Sir Keith OBE, an Australian businessman and philanthropist.
The name Keith experienced significant fluctuations in popularity over the years, with a total of 2216 babies named Keith between 1900 and 2007. The name's peak occurred in 1957 with 46 births, followed by another high point in 1968 with 73 births. However, popularity began to decline significantly after the 1980s, with fewer than 20 births per year recorded from 1991 onwards, suggesting that the name Keith has become less common in recent decades.