a cartilaginous plate between the epiphysis & the diaphysis; it is responsible for the lengthwise growth of long bones
within growing bones this cartilage (hyaline) region (between the epiphysis and diaphysis) allows lengthwise growth of a bone. In the puberty, rapid growth in this region leads to height increase, which then ossifies in the adult. ( More? Musculoskeletal Notes)
The epiphyseal plate is the disk of cartilage between the shaft and epiphysis of a long bone during its growth. It disappears following cessation of lengthwise growth.