Centre

Centre, Center, sen′tėr, n. the middle point of anything, esp. a circle or sphere: the middle: the point toward which all things move or are drawn: the chief leader of an organisation—head-centre: the men of moderate political opinions in the French Chamber, sitting right in front of the president, with extreme men on the right and on the left—further subdivisions are Right-centre and Left-centre: the Ultramontane party in Germany.—v.t. to place on or collect to a centre.—v.i. to be placed in the middle:—pr.p. cen′tring, cen′tering; pa.p. cen′tred, cen′tered.—adj. Cen′tral, belonging to the centre, principal, dominant: belonging to a nerve-centre, of affections caused by injury to the brain or spinal cord.—ns. Centralisā′tion, Cen′tralism, the tendency to administer by the sovereign or central government matters which would be otherwise under local management.—v.t. Cen′tralise, to draw to a centre.—n. Central′ity, central position.—advs. Cen′trally, Cen′trically.—ns. Cen′tre-bit, a joiner's tool, turning on a centre, for boring circular holes—one of the chief tools of the burglar; Cen′tre-board, a shifting keel, fitted to drop below and in line with the keel proper in order to increase or diminish the draught of a boat—much used in United States racing yachts; Cen′tre-piece, an ornament for the middle of a table, ceiling, &c.—adjs. Cen′tric, Cen′trical, relating to, placed in, or containing the centre.—ns. Cen′tricalness, Centric′ity; Cen′trum, the body of a vertebra.—Central fire, said of a cartridge in which the fulminate is placed in the centre of the base, as opposed to rim fire; Central forces, forces whose action is to cause a moving body to tend towards a fixed point called the centre of force.—Centre of attraction, the point to which bodies tend by the force of gravity; Centre of buoyancy, or displacement, the point in an immersed body at which the resultant vertical pressure may be supposed to act; Centre of gravity, a certain point, invariably situated with regard to the body, through which the resultant of the attracting forces between the earth and its several molecules always passes; Centre of inertia, or mass, the centre of a set of parallel forces acting on all the particles of a body, each force being proportional to the mass of the particle on which it acts; Centre of oscillation, the point in a body occupied by that particle which is accelerated and retarded to an equal amount, and which therefore moves as if it were a single pendulum unconnected with the rest of the body; Centre of percussion, the point in which the direction of a blow, given to a body, intersects the plane in which the fixed axis and the centre of inertia lie, making the body begin to rotate about a fixed axis, without causing any pressure on the axis; Centre of pressure, the point at which the direction of a single force, which is equivalent to the fluid pressure on the plane surface, meets the surface. [Fr.,—L. centrum—Gr. kentron, a sharp point.]