in Astronomy, denotes a hollow globe or sphere.

ORB, in tactics, is the disposing of a number of soldiers in circular form of defence. The orb has been thought of consequence enough to employ the attention of the famous Marshal de Puysegur in his Art of War, who prefers this position to throw a body of infantry in an open country, to resist cavalry, or even a superior force of infantry; because it is regular, and equally strong, strong, and gives an enemy no reason to expect better success by attacking one place than another. Caesar drew his whole army in this form, when he fought against Labienus. The whole army of the Gauls were formed into an orb, under the command of Sabinus and Cotta, when fighting against the Romans. The orb was generally formed fix deep.