1.The joint or bend of the arm; the outer curve in the middle of the arm when bent. "Her arms to the elbows naked."
2.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.
3.(Arch.) 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. Note: Elbow is used adjectively or as part of a compound, to denote something shaped like, or acting like, an elbow; as, elbow joint; elbow tongs or elbow-tongs; elbowroom, elbow-room, or elbow room.