in the military art, is the putting two ranks or files of soldiers into one. Thus, when the word of command is, double your ranks, the second, fourth, and fifth ranks march into the first, third, and fifth, so that the six ranks are reduced to three, and the intervals between the ranks become double what they were before.

among hunters, who say that a hare doubles, when she keeps in plain fields, and winds about to deceive the hounds.

in the menage, a term used of a horse, who is said to double his reins, when he leaps several times together, to throw his rider; thus we say, the raimingne doubles his reins, and makes pontlevis.

in navigation, the act of failing round, or passing beyond, a cape or promontory, so as that the cape or point of land separates the ship from her former situation, or lies between her and any distant observer.