prisoners' bars
/ˌprɪznəz ˈbɑːz/(also prisoners bars, prisoner's bars)
noun
A chasing game played by two sides occupying distinct areas, the object being to catch and take prisoner any player from the other side running from his or her home area.
Origin
Late 18th century; earliest use found in John Byng (1743–1813), diarist. From the genitive of prisoner + the plural of bar.