Olecranon
The olecranon from the Greek olene meaning elbow and kranon meaning head is the large, thick, curved bony eminence of the ulna, a long bone in the forearm that projects behind the elbow. It forms the most pointed portion of the elbow and is opposite to the cubital fossa or elbow pit. The olecranon serves as a lever for the extensor muscles that straighten the elbow joint.
Wikipedia
Olecranon (noun)
The bony process at the top of the ulna forming the point of the elbow.
Olecranal (adjective)
Of or pertaining to the olecranon.
Wiktionary
Olecranon (noun)
a bony prominence at the elbow, on the upper end of the ulna.
Oxford Dictionary