William John Thoms (16 November 1803 – 15 August 1885) was a British writer credited with coining the term "folklore" in the 1840s. Thoms's investigation of folklore and myth led to a later career of debunking longevity myths. Hence, he is the "father of age validation research" to demographers. Thoms was an antiquary and miscellaneous writer, for many years a clerk in the secretary's office of Chelsea Hospital. He was in 1845 appointed Clerk, and subsequently Deputy Librarian to the House of Lords. He was the founder in 1849 of Notes and Queries, which for some years he also edited.