Femur and Loin

Femur noun - The longest and thickest bone of the human skeleton; extends from the pelvis to the knee.

Loin and femur are semantically related In some cases you can use "Loin" instead a noun "Femur".

Loin noun - Either side of the backbone between the hipbone and the ribs in humans as well as quadrupeds.

Femur and loin are semantically related in leg part topic. You can use "Femur" instead a noun "Loin".