JOINT, in anatomy, the union of any two segments of an animal body, through the intervention of a structure or struc tures different from both. The different kinds of joints may be thus classified: 1. Synarthrosis: (1) Suture, (2) Schin dylesis, (3) Gomphosis, (4) Amphiar throsis. 2. Diarthrosis: (1) Arthro dia, (2) Enarthrosis, (3) Ginglymus, and (4) Diarthrosis rotatorius. The terms symphysis, synchondrosis, syneuro sis, syssarcosis, and meningosis, former ly applied to joints, are now discarded.
In carpentry, a mode of securing to gether the meeting edges of wooden structures; the place where one piece of timber is united to another. The straight joint is where the edges make a butt joint, being planed straight. Timbers are generally joined by mortises and ten ons, or by straps and bolts. The various kinds of joints are named according to their forms and uses, thus: (1) A but ting joint, in carpentry, is one in which the fibers of one piece are perpendicular to those of the other; in machinery, one in which the pieces meet at right angles. (2) A bevel joint, one in which the plane of the joint is parallel to the fibers of one piece and oblique to those of the other. (3) Dove-tail joint. (4) A longi tudinal joint is one in which the common seam runs parallel with the fibers of both. (5) A miter joint, one formed by the meeting of matching pieces in a frame, the parts uniting on a line bisect ing the angle, which is usually, but not necessarily, one of 90°. (6) A square
joint, one in which the plane of the joint is at right angles to the fibers of one piece, and parallel to those of the other.
In geology, a natural fissure or line of parting traversing rocks in a straight and well-determined line, often at right angles to the planes of stratification.
In masonry, the face-joints of vous soirs are those which appear on the face of the arch. The vertical joint is be tween stones of the same course. The horizontal joint is between courses. The coursing-joint is the joint between the courses of voussoirs. The heading-joint is that between two voussoirs in the same course. The flush-joint is filled up to tbe face by pointing with mortar.
In plumbing! the sheets of sheet-metal roofing are joined by a drip-joint or a flashing-joint in eases where they are not soldered. A flush-joint or jump-joint is a butt joint covered with a plate on the inner side, called the butt plate. In a lap-joint the pieces overlap each other.
The. word is also applied in slang to an opium-smoking den; or any resort of bad repute.