Turnstile

Pronunciation

• UK IPA: /ˈtɜːnstaɪəl/
• US IPA: /ˈtɝːnstaɪəl/

Origin

turn (rotating) + stile (gate)

Full definition of turnstile

Noun

1. A rotating mechanical device that controls and counts passage between public areas, especially one that only allows passage after a charge has been made.
2. (mathematics, logic, proof theory) The $\backslash vdash$ symbol used to represent logical entailment (deducibility relation), especially of the syntactic type, i.e., syntactic consequence. (Such symbol can be read as "proves".

1. Comma-separated elements preceding the turnstile should be interpreted as forming a conjunction, whereas comma-separated elements following the turnstile should be interpreted as forming a disjunction.

Related terms

• (mathematics, logic) double turnstile