Turnstile

Part of speech: noun

Pronunciation: /ˈtɜːnstaɪl/

Definitions

1. A device designed to permit passage through rotation while preventing unauthorized access at places like transit systems or public events
2. A revolving entry mechanism that allows movement in one direction while restricting the opposite flow, prevalent in public transportation and entertainment venues
3. A rotating barrier that allows one person at a time to pass, commonly used to control access in public places

Etymology: Turnstile is a plain compound: "turn" plus "stile." The "turn" half traces back through Middle English "turnen" and Old French "torner" to Latin "tornare," meaning to turn on a lathe, and ultimately to a Greek word for a lathe or pair of compasses. The "stile" half is older and more physical, coming from Old English "stigel," a step or ladder over a fence or wall. The surprise is that the second part started out as a way over an obstacle rather than through it. A stile was a set of steps, often with a gap for a person, letting walkers cross a fence without opening a gate. The turnstile took that same job and gave it a moving part: a set of arms that rotates so one person passes at a time, keeping livestock or crowds in check.

Synonyms: gate, barrier, entrance, access point, checkpoint