Jack is a given name, a diminutive of John; alternatively, it may be derived from Jacques, the French form of James or Jacob. Since the late 20th century, Jack has become one of the most common names for boys in many English-speaking countries. It may also be a short form of the male name Jackson. Jack is also used to a lesser extent as a female given name, often as a shortened version of Jacqueline. The word "jack" is also commonly used in other contexts in English for many occupations, objects and actions, linked to the use of the word as a metaphor for a common man. Origin Jack is thought by some to have hailed from the earlier Jackin (from the name Jankin). Alternatively, it may be derived from an anglicisation of Jacques, the French form of the name James or Jacob. There is also a theory that it is Celtic in origin, meaning "healthy, strong, full of vital energy" (compare the Welsh word iach, "health"), from a putative Ancient British Yakkios. Both the name and the word "jack" were long used as a term to refer to any man, especially of the common classes. Frequency In several English-speaking countries, Jack has become increasingly used as a formal name, rather than being a mere nickname as it traditionally has been. In its own right, it is now more popular than John, James, and Jacob. In recent years, Jack has been the most common given name for boys in the United Kingdom, Ireland, and Australia, and has grown in popularity in the United States. John–from which Jack was often derived—was, along with William, the most frequent male name throughout the 19th century and in the first half of the 20th century. Jack appeared on the lists of the most frequently used male-baby names in the UK for 2003–2007. In 2014, Jack was again the most popular name for baby boys in Ireland. In 2008, 2009, 2010, and 2013, Jack was the most common name given to boys in Australia. According to the United States Census of 1990, Jack is an uncommon American name, the given name for 0.315% of the male population and 0.001% of the female population. However, the frequency of Jack as a baby name has steadily increased from the 160–170 rank prior to 1991 to a rank of 35 in 2006. Jock is a common diminutive of