骨骼 (gǔ gé) is the formal, anatomical term for the entire skeleton or the collective bones of a human or animal. It is more scientific and written than 骨头 (gǔ tou), which refers to individual bones or is used in everyday speech and figurative expressions. 骨架 (gǔ jià) also means 'skeleton' but often implies the structural framework of a body or object, whereas 骨骼 is strictly the biological skeleton.