joint / joint/ • n. 1. a point at which parts of an artificial structure are joined. ∎  Geol. a break or fracture in a mass of rock, with no relative displacement of the parts. ∎  a piece of flexible material forming the hinge of a book cover. 2. a structure in the human or animal body at which two parts of the skeleton are fitted together. ∎  each of the distinct sections of a body or limb between the places at which they are connected: the top two joints of his index finger. ∎  Brit. a large piece of meat cooked whole or ready for cooking: a joint of ham. ∎  the part of a stem of a plant from which a leaf or branch grows. ∎  a section of a plant stem between such parts; an internode. 3. inf. an establishment of a specified kind, esp. one where people meet for eating, drinking, or entertainment: a burger joint. ∎  (the joint) prison. 4. inf. a marijuana cigarette.• adj. shared, held, or made by two or more people or organizations together: the companies issued a joint statement. ∎  shared, held, or made by both houses of a bicameral legislature: a joint session of Congress a joint congressional hearing. ∎  sharing in a position, achievement, or activity: a joint winner. ∎  Law applied or regarded together. Often contrasted with several.• v. [tr.] 1. provide or fasten (something) with joints: [as adj.] (jointed) jointed lever arms. ∎  fill up the joints of (masonry or brickwork) with mortar; point. ∎  prepare (a board) for being joined to another by planing its edge. 2. cut (the body of an animal) into joints.PHRASES: out of joint (of a joint of the body) out of position; dislocated: he put his hip out of joint. ∎  in a state of disorder or disorientation: time was thrown completely out of joint.DERIVATIVES: joint·less adj.joint·ly adv.

joint
1. A discrete brittle fracture in a rock along which there has been little or no movement parallel to the plane of fracture, but slight movement normal to it. Fracture may be caused by shrinkage, due to cooling or desiccation, or to the unloading of superincumbent rocks by erosion or tectonism. A group of joints of common origin constitutes a ‘joint set’ and the joints are usually planar and parallel or sub-parallel in orientation. ‘Joint systems’ comprise two or more joint sets, which are usually arranged systematically with respect to the principal stress axes of regional deformation. Cooling joints (shrinkage joints), such as those which split a rock into long prisms or columns to form ‘columnar joints’, most commonly found in lavas, are due to differential volume changes in cooling and contracting magmas. Unloading joints result from erosional unloading of the crust and form flat-lying, sheet-like joint sets, e.g. those found in granitic rocks.

2. See VOIDS, TYPES OF.

joint The point of contact between two (or more) bones, together with the tissues that surround it. Joints fall into three classes that differ in the degree of freedom of movement they allow: (1) immovable joints, e.g. the sutures between the bones that form the cranium; (2) slightly movable joints, e.g. the symphyses between the vertebrae of the spinal column; and (3) freely movable or synovial joints, e.g. those that occur between the limb bones. Synovial joints include the ball-and-socket joints (between the limbs and the hip and shoulder girdles), which allow movement in all directions; and the hinge joints (e.g. at the knee and elbow), which allow movement in one plane only (see illustration). A synovial joint is bound by ligaments and lined with synovial membrane.

joint In anatomy, place where one bone meets another. In movable joints, such as those of the knee, elbow and spine, the bones are separated and cushioned from one another by pads of cartilage. In fixed joints, cartilage may be present in infancy but disappear later as the bones fuse together, as in the skull. In the movable joints of bony vertebrates, the bones are held together by ligaments. Synovial fluid lubricates the joint.

joint (joint) n. the point at which two or more bones are connected. The opposing surfaces of bone are lined with cartilaginous, fibrous, or soft (synovial) tissue. See also amphiarthrosis, diarthrosis, synarthrosis.