in the modern fortification, a huge mass of earth, faced usually with sods, sometimes with brick, and rarely with stone, standing out from a rampart whereof it is a principal part, and is what, in the ancient fortification, was called a bulwark.

Solid BASTIONS, are those that have the void space within them filled up entirely, and raised of an equal height with the rampart.

Void and Hollow BASTIONS, are those that are only surrounded with a rampart and parapet, having the space within void and empty, where the ground is so low, that, if the rampart be taken, no retrenchment can be made in the centre, but what will lie under the fire of the besieged.

Flat BASTION, is a bastion built in the middle of the curtain, when it is too long to be defended by the battalion at its extremes.

Cut BASTION, is that whose point is cut off, and instead thereof has a re-entering angle, or an angle inwards, with two points outwards; and is used either when without such a contrivance the angle would be too acute, or when water or some other impediment hinders the carrying on the battalion to its full extent.

Compounded BASTION, is when two sides of the interior polygon are very unequal, which makes the gorges also unequal.

Deformed BASTION, is when the irregularity of the lines and angles makes the bastion out of shape; as when it wants one of its demigorges, one side of the interior polygon being too short.

Demi-BASTION, is composed of one face only, and but one flank, and a demigorge.

Double BASTION, is that which is raised on the plane of another battalion.

Regular BASTION, is that which has its true proportion of faces, flanks, and gorges.

BASTION of France, a fortres on the coast of Barbary, belonging to the French.