Olecranon: The bony tip of the elbow. The olecranon is the near end of the ulna, the bone in the forearm, and it forms the pointed portion of the elbow. The triceps muscle tendon of the back of the arm attaches to the olecranon. Disease can affect the olecranon. For example, inflammation of the tiny fluid-filled sac (bursa) at the tip of the elbow can occur; this is referred to as olecranon bursitis. A firm nodule can form at the tip of the elbow; it is referred to as an olecranon nodule and is sometimes found in gout or rheumatoid arthritis. Also known as the olecranon process of the ulna.