Endochondral refers to a process of bone development where cartilage is replaced by bone tissue. This process is crucial during the growth of long bones, such as those in the arms and legs, and occurs primarily during fetal development and childhood. In endochondral ossification, a cartilage model forms first, which is gradually transformed into bone through the action of cells called osteoblasts. This method of bone formation is essential for the proper growth and shaping of the skeleton, allowing for the development of a strong and functional human body.