Your knee is simply called your knee. While it's made up of a few parts, including the tibiofemoral joint, which is the part between the thigh bone (femur) and the shin bone (tibia), and the patellofemoral joint, which is between the thigh bone (femur) and the kneecap (patella), the entire structure is still referred to as the knee.
However, if you're looking for a more specific term, you can refer to it as the knee joint.
