ossification
formation of bone or of a bony substance, or the conversion of fibrous tissue or of cartilage into bone or a bony substance
en-US/ˌɑsəfəˈkeɪʃən/
en-GB/ˌɒsɪfɪˈkeɪʃən/
formation of bone or of a bony substance, or the conversion of fibrous tissue or of cartilage into bone or a bony substance