5. To bring into a certain order, arrangement, classification, etc.; to bring under rules or within certain
limits of descriptions and terms adapted to use in computation; as, to reduce animals or vegetables to a
class or classes; to reduce a series of observations in astronomy; to reduce language to rules.
6. (Arith.) (a) 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. (b) To change the form of a quantity or expression without altering its value; as, to reduce fractions
to their lowest terms, to a common denominator, etc.
7. (Chem.) To bring to the metallic state by separating from impurities; hence, in general, to remove
oxygen from; to deoxidize; to combine with, or to subject to the action of, hydrogen; as, ferric iron is reduced
to ferrous iron; or metals are reduced from their ores; — opposed to oxidize.
8. (Med.) To restore to its proper place or condition, as a displaced organ or part; as, to reduce a
dislocation, a fracture, or a hernia.
Reduced iron (Chem.), metallic iron obtained through deoxidation of an oxide of iron by exposure
to a current of hydrogen or other reducing agent. When hydrogen is used the product is called also
iron by hydrogen. — To reduce an equation (Alg.), to bring the unknown quantity by itself on one
side, and all the known quantities on the other side, without destroying the equation. — To reduce an
expression (Alg.), to obtain an equivalent expression of simpler form. — To reduce a square (Mil.),
to reform the line or column from the square.
Syn. — To diminish; lessen; decrease; abate; shorten; curtail; impair; lower; subject; subdue; subjugate; conquer.
