REACTION n.
(Mech.), a water wheel driven by the reaction of water, usually one in which the water, entering it centrally, escapes at its periphery in a direction opposed to that of its motion by orifices at right angles, or inclined, to its radii.
REDUCE v. 2 definitions
To change, as numbers, from one denomination into another without altering their value, or from one denomination into others of the same value; as, to reduce pounds, shillings, and pence to pence, or to reduce pence to pounds; to reduce days and hours to minutes, or minutes to days and hours.