A tight girth. Hence an advantage over the one cinched. Sp. cincha.

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1872.  I leaned down and felt of the cinch, to see if it had slipped.—C. King, ‘Sierra Nevada,’ p. 119. (N.E.D.)

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1888.  The saddle was also secured by a cinch or girth of cow’s-hair, which hard riders found a great help in keeping the saddle firm.—Mrs. Custer, ‘Tenting on the Plains,’ p. 212.

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1888.  Black and blue thinks the Dwyers have a cinch on both the great events.—Daily Inter-Ocean, Feb. 2 (Farmer).

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1909.  You have a cinch such as no man ever possessed.—Chicago Evening Post, Feb.

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