turnstile[
'tә:nstail]
n. 十

转门
turnstile[ noun ]a gate consisting of a post that acts as a pivot for rotating arms; set in a passageway for controlling the persons entering<noun.artifact> 
Turnstile \Turn"stile`\, n.
1. A revolving frame in a footpath, preventing the passage of
horses or cattle, but admitting that of persons; a
turnpike. See {Turnpike}, n., 1.
2. A similar arrangement for registering the number of
persons passing through a gateway, doorway, or the like.