also: こつか
noun, noun or participle which takes 'suru', intransitive verb
Medical/biological term for the process of bone formation. Can be used literally or figuratively for hardening into a rigid state.
軟骨が骨化して硬い骨になる。
Cartilage ossifies and becomes hard bone.
組織の骨化が進むと柔
As ossification of the tissue progresses, flexibility is lost.