Bone density refers to the amount of mineral matter per square centimeter of bone. It is an important measure of bone strength and health, indicating how dense and solid the bones are. Higher bone density generally means stronger bones, which can better withstand fractures and other injuries. Bone density can be affected by various factors, including age, diet, and physical activity. Conditions such as osteoporosis can lead to decreased bone density, making bones more fragile. Regular exercise, a balanced diet rich in calcium and vitamin D, and avoiding smoking can help maintain healthy bone density throughout life.