CENTESIMATION, in ancient military history, a mild kind of military punishment, in cases of desertion, mutiny, and the like, when only every 100th man was executed. CENTER, CENTRE, in a general sense, signifies a point equally distant from the extremities of a line, surface, or solid. CENTRE _of a battalion_, on parade, is the middle, where an interval is left for the colors; of an encampment, it is the main street: and on a march, is an interval for the baggage, &c. CENTRE _of a bastion_, is a point in the middle of the gorge of the bastion, from whence the capital line commences, and which is generally at the inner polygon of the figure. CENTRE _of gravity_, in military mechanics, is that point about which the several parts of a body exactly balance each other in any situation. CENTRE _of a conic section_, is the point where all the diameters meet. CENTRE _of an ellipsis_, is that point where the transverse and conjugate diameters intersect each other. CENTRE _of motion_, is that point which remains at rest while all the other parts of the body move about it. CENTRE _of percussion_, is that point in which the force of the stroke is the greatest possible. When the moving body revolves round a fixed point, the centre of percussion is the same with the centre of oscillation, and found by the same method; but when the body moves in a parallel direction, the centre of percussion is the same with the centre of gravity. CENTINEL, CENTRY, is a private soldier from the guard, posted upon any spot of ground, to stand and watch carefully for the security of the guard, or of any body of troops, or post, and to prevent any surprise from the enemy. All centinels are to be very vigilant on their posts; neither are they to sing, smoke, or suffer any noise to be made near them. They are not to sit down, lay their arms out of their hands, or sleep; but keep moving about on their posts during the two hours they stand, if the weather will allow of it. No centry to move more than 50 paces to the right, and as many to the left of his post, and let the weather be ever so bad, he must not get under any other cover, but that of the centry box. No one to be allowed to go from his post without leave from his commanding officer; and, to prevent desertion or marauding, the centries and vedettes must be charged to let no soldier pass. CENTINEL _perdu_, a soldier posted near an enemy in some very dangerous post, where he is in perpetual danger of being shot or taken. CENTRY-_box_, a sort of box, or hut, to shelter the centinel from the injuries of the weather; in fortifications they are sometimes made of masonry, and of stone, in a circular form. CENTURION, a military officer among the ancient Romans; who commanded an (_centum_) hundred men. The term is now obsolete. It answers to the modern captain of a company. CENTURY, in a military sense, means a hundred soldiers, who were employed in working the battering-ram.