What is the process where bones fuse together?

The process where bones fuse together is called "ossification" or "bone fusion." This can occur naturally during growth and development, particularly in areas such as the spine or skull, where individual bones merge to form a single structure. It can also happen in response to injury or stress, leading to conditions like ankylosis, where joints become stiff due to bone growth. In some cases, surgical procedures may be performed to intentionally fuse bones for stability or healing.