v. t. [ 1st pref. un- + double. ] To unfold, or render single. [ 1913 Webster ]

v. i. 1. To be increased to twice the sum, number, quantity, length, or value; to increase or grow to twice as much. [ 1913 Webster ]

'T is observed in particular nations, that within the space of three hundred years, notwithstanding all casualties, the number of men doubles. T. Burnet. [ 1913 Webster ]

2. To return upon one's track; to turn and go back over the same ground, or in an opposite direction. [ 1913 Webster ]

Doubling and turning like a hunted hare. Dryden. [ 1913 Webster ]

Doubling and doubling with laborious walk. Wordsworth. [ 1913 Webster ]

3. To play tricks; to use sleights; to play false. [ 1913 Webster ]

What penalty and danger you accrue,
If you be found to double. J. Webster. [ 1913 Webster ]

4. (Print.) To set up a word or words a second time by mistake; to make a doublet. [ 1913 Webster ]

To double upon (Mil.), to inclose between two fires. [ 1913 Webster ]

adv. Twice; doubly. [ 1913 Webster ]

I was double their age. Swift. [ 1913 Webster ]

n. 1. Twice as much; twice the number, sum, quantity, length, value, and the like. [ 1913 Webster ]

If the thief be found, let him pay double. Ex. xxii. 7. [ 1913 Webster ]

2. Among compositors, a doublet (see Doublet, 2.); among pressmen, a sheet that is twice pulled, and blurred. [ 1913 Webster ]

3. That which is doubled over or together; a doubling; a plait; a fold. [ 1913 Webster ]

Rolled up in sevenfold double
Of plagues. Marston. [ 1913 Webster ]

4. A turn or circuit in running to escape pursues; hence, a trick; a shift; an artifice. [ 1913 Webster ]

These men are too well acquainted with the chase to be flung off by any false steps or doubles. Addison. [ 1913 Webster ]

5. A person or thing that is the counterpart of another; a duplicate; copy; (Obs.) transcript; -- now chiefly used of persons. Hence, a wraith. [ 1913 Webster ]

My charming friend . . . has, I am almost sure, a double, who preaches his afternoon sermons for him. Atlantic Monthly. [ 1913 Webster ]

6. A player or singer who prepares to take the part of another player in his absence; a substitute; -- used especially of a person who resembles an actor and takes the actor's place in scenes requiring special skills; as, a stunt double. [ 1913 Webster +PJC ]

7. Double beer; strong beer. [ 1913 Webster ]

8. (Eccl.) A feast in which the antiphon is doubled, hat is, said twice, before and after the Psalms, instead of only half being said, as in simple feasts. Shipley. [ 1913 Webster ]

9. (Lawn Tennis) A game between two pairs of players; as, a first prize for doubles. [ 1913 Webster ]

10. (Mus.) An old term for a variation, as in Bach's Suites. [ 1913 Webster ]

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 ]

☞ 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 (‡) next to the 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 ]

v. t. [ imp. & p. p. Doubled p. pr. & vb. n. Doubling ] [ OE. doblen, dublen, doublen, F. doubler, fr. L. duplare, fr. duplus. See Double, a. ] 1. To increase by adding an equal number, quantity, length, value, or the like; multiply by two; as, to double a sum of money; to double a number, or length. [ 1913 Webster ]

Double six thousand, and then treble that. Shak. [ 1913 Webster ]

2. To make of two thicknesses or folds by turning or bending together in the middle; to fold one part upon another part of; as, to double the leaf of a book, and the like; to clinch, as the fist; -- often followed by up; as, to double up a sheet of paper or cloth. Prior. [ 1913 Webster ]

Then the old man
Was wroth, and doubled up his hands. Tennyson. [ 1913 Webster ]

3. To be the double of; to exceed by twofold; to contain or be worth twice as much as. [ 1913 Webster ]

Thus reënforced, against the adverse fleet,
Still doubling ours, brave Rupert leads the way. Dryden. [ 1913 Webster ]

4. To pass around or by; to march or sail round, so as to reverse the direction of motion. [ 1913 Webster ]

Sailing along the coast, the doubled the promontory of Carthage. Knolles. [ 1913 Webster ]

5. (Mil.) To unite, as ranks or files, so as to form one from each two. [ 1913 Webster ]

a. Acting or operating in two directions or with both motions; producing a twofold result; as, a double-acting engine or pump. [ 1913 Webster ]

v. t. (Naut.) To row by rowers sitting side by side in twos on a bank or thwart. [ 1913 Webster ]

To double-bank an oar, to set two men to pulling one oar. [ 1913 Webster ]

a. Applied to a kind of rowing in which the rowers sit side by side in twos, a pair of oars being worked from each bank or thwart.

See under Valve. [ 1913 Webster ]

a. Folding or lapping over on the breast, with a row of buttons and buttonholes on each side; as, a double-breasted coat. [ 1913 Webster ]