Elbow n. : The joint or bend of the arm; the outer curve in the middle of the arm when bent.

Elbow n. : Any turn or bend like that of the elbow, in a wall, building, and the like; a sudden turn in a line of coast or course of a river; also, an angular or jointed part of any structure, as the raised arm of a chair or sofa, or a short pipe fitting, turning at an angle or bent.

Elbow n. : A sharp angle in any surface of wainscoting or other woodwork; the upright sides which flank any paneled work, as the sides of windows, where the jamb makes an elbow with the window back.

Elbow v. t. : To push or hit with the elbow, as when one pushes by another.

Elbow v. i. : To jut into an angle; to project or to bend after the manner of an elbow.

Elbow v. i. : To push rudely along; to elbow one's way.

Example:
What size Elbow macaroni do you use to make Hawaiian macaroni salad?

Taxonomy
elbow, carrying angle, elbow-joint, ulna, elbow joint, movements, radius, capsule, radius and ulna, synovial membrane, injuries, Elbow Dislocation, humerus, Fractures, flexion, head of the radius, three bones, collateral ligaments.

Defination from the web:
elbow is the region surrounding the elbow-joint[1]—the ginglymus or hinge joint in ... Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ...