IPA: /ˈtɜrnstaɪl/
KK: /ˈtɜrnˌstaɪl/
A mechanical device that allows people to enter or exit a place, usually found in public areas like train stations or amusement parks, where it only lets one person through at a time.
We had to use the turnstile to enter the subway station.
Turnstile → It is formed from "turn" (from Old English "turnian", meaning to rotate or revolve) and "stile" (from Old English "stigel", meaning a step or a way). The word "turnstile" refers to a gate that rotates to allow entry or exit, functioning as a step or passage that turns.
Think of a gate that 'rotates' ('turn') to let you 'step' ('stile') through — that's how a turnstile works.