Femur/ˈfiːmər/ Definition 1 of 1Pro Tip 1/3Anatomy Reference Used often in medical or anatomical contexts to discuss leg injuries or surgeries. The X-ray showed his femur was intact after the accident. Pro Tip 2/3Injury Severity A broken femur is considered a serious injury because it's a major bone. Due to the severity of the broken femur, an ambulance was called immediately. Pro Tip 3/3Scientific Contexts Used in evolutionary biology to discuss human and animal skeletal structure. The fossilized femur suggests that the dinosaur walked on two legs.