What is "columbjohn"

Columb John (today "Columbjohn") in the parish of Broadclyst in Devon, England, is an historic estate and was briefly the seat of the prominent Acland family which later moved to the adjacent estate of Killerton. Nothing of the structure of the Acland mansion house survives except the arch to the gatehouse, dated about 1590, and the private chapel, restored in 1851. The site of the former mansion house is situated one mile due west of Killerton House, and five miles north-east of the historic centre of the City of Exeter. The estate's name derives from it having been held by the Culme family, whose own name was taken from its landholdings in the vicinity of the River Culm, which flows through the Columb John estate.