Ossify/ˈɑːsɪfaɪ/ Definition 1 of 2Pro Tip 1/3Medical Context Often used in medicine to describe how tissues transform within the body. When a baby grows, cartilage in their body ossifies to become bone. Pro Tip 2/3Metamorphosis Indicates a physiological process; signifies a permanent developmental change. The tadpole's tail gradually ossified as it turned into a frog. Pro Tip 3/3Natural Progression Used to describe a natural and expected process in growth or healing. The doctor explained how the broken rib will ossify and heal over time.