The outer hard covering of the bone is called the periosteum in Arabic. It is a thin, fibrous membrane that covers the entire surface of the bone, except for the ends of the bones that are covered with cartilage. The periosteum is responsible for the blood supply to the bone and for the production of new bone cells. It also helps to protect the bone from damage.
In English, the periosteum is also called the bone periosteum. It is sometimes referred to as the bone membrane.
Here are some other terms related to bones in Arabic:
عظم (ʻaẓm): bone
نخاع العظم (nakhāʻ al-ʻaẓm): bone marrow
نسيج عظمي (nasīj ʻaẓmī): bone tissue
هيكل عظمي (haykal ʻaẓmī): skeleton
مفصل (mafṣal): joint
غضروف (ġaḍrūf): cartilage
كسر (kasr): fracture
I hope this helps! Let me know if you have any other questions.