in geometry, a quantity extended in length only, without any breadth or thickness. It is formed by the flux or motion of a point. See Fluxions, and Geometry.

the art of war, is understood of the disposition of an army, ranged in order of battle, with the front extended as far as may be, that it may not be flanked.

Line of battle, is also understood of the disposition of a fleet on the day of the engagement, on which occasion the vessels are usually drawn up as much as possible in a straight line, as well to gain and keep the advantage of the wind, as to run the same board.

Ship of the Line, a vessel large enough to be drawn up in the line, and to have a place in a sea-fight.

genealogy, a series or succession of relations in various degrees, all descending from the same common father.