Medieval English pet form of John — god is gracious. So common in medieval England that "jack" became a word for an ordinary man.
Jack ranks 15th among American boys in 2025, with 8,754 born that year. Its best year was 1927, when 12,884 babies were given the name, ranking 16th. The typical living American called Jack is about 28 years old today. It is relatively most common in Vermont, where it accounts for 1.10% of births.
Source: US Social Security Administration, national and state name files, 2025 release, and the Office for National Statistics for England and Wales. Etymology researched and written by our editors. Living-population and median-age figures are our own estimates, described in the methodology.