Roots:

osteo– : of or relating to bone (Greek)

–necro : death (Greek)

–osis : a process or condition (Greek)

Based on these roots, we can assume that osteonecrosis is a process involving bone death.

Osteonecrosis occurs when there is a lack of blood supply to bone tissue, causing tiny breaks in the bone, eventually causing it to collapse. An injury like a broken bone or dislocated joint might damage blood vessels leading to the bone resulting in reduced blood flow to the bone. Additionally, excessive alcohol consumption and steroid use may lead to fatty deposits in blood vessels contributing to low blood supply to bones.

Diagram shows osteonecrotic bone (left) compared to healthy bone (right). The osteonecrotic bone has reduced bone density as a result of low blood flow. Image credit: https://www.spineorthocenter.com/services/orthopedic/joint-diseases/osteonecrosis/