head gate: a gate upstream from a lock or canal that is used to control the flow of water at the upper end
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
kuru: a progressive disease of the central nervous system marked by increasing lack of coordination and advancing to paralysis and death within a year of the appearance of symptoms; thought to have been transmitted by cannibalistic consumption of diseased brain tissue since the disease virtually disappeared when cannibalism was abandoned