Double refraction

Double Dou"ble (d[u^]b"'l), a. [OE. doble, duble, double, OF. doble, duble, double, F. double, fr. L. duplus, fr. the root of duo two, and perh. that of plenus full; akin to Gr. diplo`os double. See {Two}, and {Full}, and cf. {Diploma}, {Duple}.] 1. Twofold; multiplied by two; increased by its equivalent; made twice as large or as much, etc. [1913 Webster]

Let a double portion of thy spirit be upon me. -- 2 Kings ii. 9. [1913 Webster]

Darkness and tempest make a double night. --Dryden. [1913 Webster]

2. Being in pairs; presenting two of a kind, or two in a set together; coupled. [1913 Webster]

[Let] The swan, on still St. Mary's lake, Float double, swan and shadow. --Wordsworth. [1913 Webster]

3. Divided into two; acting two parts, one openly and the other secretly; equivocal; deceitful; insincere. [1913 Webster]

With a double heart do they speak. -- Ps. xii. 2. [1913 Webster]

4. (Bot.) Having the petals in a flower considerably increased beyond the natural number, usually as the result of cultivation and the expense of the stamens, or stamens and pistils. The white water lily and some other plants have their blossoms naturally double. [1913 Webster]

Note: Double is often used as the first part of a compound word, generally denoting two ways, or twice the number, quantity, force, etc., twofold, or having two. [1913 Webster]

{Double base}, or {Double bass} (Mus.), the largest and lowest-toned instrument in the violin form; the contrabasso or violone.

{Double convex}. See under {Convex}.

{Double counterpoint} (Mus.), that species of counterpoint or composition, in which two of the parts may be inverted, by setting one of them an octave higher or lower.

{Double court} (Lawn Tennis), a court laid out for four players, two on each side.

{Double dagger} (Print.), a reference mark ([dag]) next to the dagger ([dagger]) in order; a diesis.

{Double drum} (Mus.), a large drum that is beaten at both ends.

{Double eagle}, a gold coin of the United States having the value of 20 dollars.

{Double entry}. See under {Bookkeeping}.

{Double floor} (Arch.), a floor in which binding joists support flooring joists above and ceiling joists below. See Illust. of Double-framed floor.

{Double flower}. See {Double}, a., 4.

{Double-framed floor} (Arch.), a double floor having girders into which the binding joists are framed.

{Double fugue} (Mus.), a fugue on two subjects.

{Double letter}. (a) (Print.) Two letters on one shank; a ligature. (b) A mail requiring double postage.

{Double note} (Mus.), a note of double the length of the semibreve; a breve. See {Breve}.

{Double octave} (Mus.), an interval composed of two octaves, or fifteen notes, in diatonic progression; a fifteenth.

{Double pica}. See under {Pica}.

{Double play} (Baseball), a play by which two players are put out at the same time.

{Double plea} (Law), a plea alleging several matters in answer to the declaration, where either of such matters alone would be a sufficient bar to the action. --Stephen.

{Double point} (Geom.), a point of a curve at which two branches cross each other. Conjugate or isolated points of a curve are called double points, since they possess most of the properties of double points (see {Conjugate}). They are also called {acnodes}, and those points where the branches of the curve really cross are called {crunodes}. The extremity of a cusp is also a double point.

{Double quarrel}. (Eccl. Law) See {Duplex querela}, under {Duplex}.

{Double refraction}. (Opt.) See {Refraction}.

{Double salt}. (Chem.) (a) A mixed salt of any polybasic acid which has been saturated by different bases or basic radicals, as the double carbonate of sodium and potassium, {NaKCO3.6H2O}. (b) A molecular combination of two distinct salts, as common alum, which consists of the sulphate of aluminium, and the sulphate of potassium or ammonium.

{Double shuffle}, a low, noisy dance.

{Double standard} (Polit. Econ.), a double standard of monetary values; i. e., a gold standard and a silver standard, both of which are made legal tender.

{Double star} (Astron.), two stars so near to each other as to be seen separate only by means of a telescope. Such stars may be only optically near to each other, or may be physically connected so that they revolve round their common center of gravity, and in the latter case are called also binary stars.

{Double time} (Mil.). Same as {Double-quick}.

{Double window}, a window having two sets of glazed sashes with an air space between them. [1913 Webster]