gatekeeper

noun

1. a person in charge of a gate, usually to identify, count, supervise, etc., the traffic or flow through it.
2. guardian; monitor: the gatekeepers of Western culture.

noun

1. a person who has charge of a gate and controls who may pass through it
2. any of several Eurasian butterflies of the genus Pyronia, esp P. tithonus, having brown-bordered orange wings with a black-and-white eyespot on each forewing: family Satyridae
3. a manager in a large organization who controls the flow of information, esp to parent and subsidiary companies