A saw for dividing timber lengthwise, usually set in a frame, and worked by two persons; also, a fret saw. [1913 Webster]
A kind of narrow ripsaw, tapering from butt to point, with hook teeth and averaging from 5 to 7Webster 1913 Suppl.]

whipsaw, v. t.

To saw with the whipsaw. [Webster 1913 Suppl.]
To defeat in, or cause to lose, two different bets at the same turn or in one play, as a player at faro who has made two bets at the same time, one that a card will lose and another that a different card will win; hence, to defeat in spite of every effort. [Webster 1913 Suppl.]
to cause to suffer a setback or losses by subjecting to two forces at the same time or in rapid succession; as, consumers were whipsawed by both inflation and higher sales taxes. [PJC]
to cause to suffer a series of losses in trading when buying and selling at the wrong times in a rapidly fluctuating market; -- especially used when an attempt is made, by selling short, to recover losses from a long purchase in a declining market, and the short sale also results in a loss when the market subsequently rises. Used mostly in the passive; as, to be whipsawed by exaggerated responses to a changing outlook. [PJC]

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OXFORD DICTIONARY

whipsaw, n. & v.
--n. a saw with a narrow blade held at each end by a frame.
--v. (past part. -sawn or -sawed)
1 tr. cut with a whipsaw.
2 US sl. a tr. cheat by joint action on two others. b intr. be cheated in this way.

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