turnstile

n. apparatus consisting of rotating bars that regulate entry

A turnstile, also called a baffle gate, is a form of gate which allows one person to pass at a time. It can also be made so as to enforce one-way traffic of people, and in addition, it can restrict passage to people who insert a coin, a ticket, a pass, or similar. Thus a turnstile can be used in the case of paid access (sometimes called a Faregate when used for this purpose), for example public transport or a pay toilet, or to restrict access to authorized people, for example in the lobby of an office building.
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Hawthorn, Wiltshire, also known as Corsham or TURNSTILE, is an immense nuclear bunker in the United Kingdom. The complex was built 120ft below RAF Rudloe Manor, Corsham, in Wiltshire from the 1940s onwards to the 1960s. Until at least the early 1990s it contained the emergency government command centre (Central Government War Headquarters).
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Noun
1. a gate consisting of a post that acts as a pivot for rotating arms; set in a passageway for controlling the persons entering
(hypernym) gate

(n.)
A similar arrangement for registering the number of persons passing through a gateway, doorway, or the like.
  

(n.)
A revolving frame in a footpath, preventing the passage of horses or cattle, but admitting that of persons; a turnpike. See Turnpike, n., 1.
  

Synonyms and related words:
French door, archway, back door, barway, bulkhead, carriage entrance, cellar door, cellarway, door, doorjamb, doorpost, doorway, front door, gate, gatepost, gateway, hatch, hatchway, lintel, porch, portal, porte cochere, postern, propylaeum, pylon, scuttle, side door, stile, storm door, threshold, tollgate, trap, trap door, turnpike