Lewis is of Welsh origin, derived from the ancient personal name 'Llewelyn'. It means 'leader' or 'famous warrior', reflecting its early historical usage among Welsh nobility. The name Lewis gained popularity in England during the Middle Ages due to the influence of the Norman-French, who brought it with them when they conquered Wales. Today, Lewis is a well-established given name throughout the English-speaking world, often associated with notable figures such as American author C.S. Lewis and former U.S. President Barack Obama's half-brother, Lewis Obama. Variant spellings include Louis and Loyd.
The name Lewis experienced significant fluctuations in popularity over the years, with a notable spike during World War I. Between 1914 and 1919, there were four peak years for the name Lewis, with totals ranging from 13 to 23 births annually. This period coincides with the high casualty rates of the war, which may have led some parents to choose the name as a tribute or remembrance. Prior to this period, the name's popularity was more consistently around the mid-teens per year. After World War I, the popularity of the name Lewis gradually declined until it reached its lowest point in recent years, with only 5 births recorded in 2004. Overall, over a span of approximately 130 years (from 1892 to 2004), there were a total of 870 births registered as Lewis.