olecranon
noun
olec·ra·non ō-ˈle-krə-ˌnän 
: the process of the ulna projecting behind the elbow joint
Word History
Etymology
New Latin, from Greek ōlekranon, from ōlenē elbow + kranion skull — more at ell, cranium
First Known Use
1578, in the meaning defined above
Medical Definition
olecranon
noun
olec·ra·non ō-ˈlek-rə-ˌnän
: the large process of the ulna that projects behind the elbow, forms the bony prominence of the elbow, and receives the insertion of the triceps muscle