three-throwadj. having three throws (see thrown.2 5), as a three-throw crank; hence, having such a crank, as three-throw pump or three-throw engine, one worked by a three-throw crank-shaft.
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three-throw1829
two-throw1875
1829 Nat. Philos. (Libr. Useful Knowl.) I. Hydraulics ii. 12 Keeping two or..three pumps constantly at work by what is called a triple or three-throw crank.
1900 Engin. Mag.19 726Three-throw ram pump for dip workings.