Chak

iron, metal, steel, iron trevet, tripod, place 8 miles to the southeast of bkra' shis lhun po in Tsang, any iron instrument or tool, lock, fetter, shackle [JV]

iron, metal [IW]

1) iron. 2) metal. 3) whip; Guardian Demon of Kilaya teachings. [RY]

...as used within context: [from The Lotus-Born, pg. 53, (ISBN 0-87773-869-6)]

"At the time of dusk, the four shvana sisters offered the core of their lives to Master Padma (Padmasambhava) and were bound under oath. At midnight, the four remati sisters offered the core of their lives and were bound under oath. At dawn, the four semo sisters offered the core of their lives and were bound under oath. Moreover, the male and female powerful sey, chak, and dung spirits all offered the core of their lives and were bound under oath, and appointed as guradians of the Vajra Kilaya teachings.