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Webster 1913 Edition

(tûrn′bŭkˊk’l)

Noun.

(Mech.)

(a)

A loop or sleeve with a screw thread at one end and a swivel at the other, – used for tightening a rod, stay, etc.

(b)

A gravitating catch, as for fastening a shutter, the end of a chain, or a hasp.