Dou″ble, 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.
Double six thousand, and then treble that. Shak.
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.
Then the old man
Was wroth, and doubled up his hands. Tennyson.
3. To be the double of; to exceed by twofold; to contain or be worth twice as much as.
Thus reënforced, against the adverse fleet,
Still doubling ours, brave Rupert leads the way. Dryden.
4. To pass around or by; to march or sail round, so as to reverse the direction of motion.
Sailing along the coast, the doubled the promontory of Carthage. Knolles.
5. (Mil.) To unite, as ranks or files, so as to form one from each two.