Jow (unit) From Wikipedia the free encyclopedia A jow (also called a jacob) is an obsolete unit of length in India approximately equal 0.25 inch (about 0.63 cm). After metrication in India in the mid-20th century, the unit became obsolete.[1] See also[edit] List of customary units of measurement in South Asia References[edit] ^ "Jow". Sizes, grades, units, scales, calendars, chronologies. Retrieved 2007-02-19. This standards- or measurement-related article is a stub. You can help Wikipedia by expanding it.vte