Femur

The femur or thigh bone is the longest, most voluminous, and strongest bone of the mammalian bodies. It forms part of the hip and part of the knee.

The word femur is Latin for thigh. In strict usage, femur bone is more proper than femur, as femur refers to thigh, and femur bone refers to the bone within it. The name of the bone itself comes from os femoris, although in modern medical usage the term femur is most often applied to the bone and not the thigh. In medical Latin its genitive is always femoris, but in classical Latin its genitive is often feminis, and should not be confused with case forms of femina, which means woman.