It's called your Hip Abductor!
Hip abduction is when the upper-leg bone, the femur, is moved out to the side and away from the body. Hip abduction exercises are important because they strengthen the muscles that stabilize the femur into the hip joint. To work the hip abductor muscles, perform the hip abduction exercises one to three times a week. These exercises will challenge and tone the hip abductor muscles.
It takes six muscles to perform hip abduction. The sartorius muscle commences at the top, front of your hip and extends into your inner, lower leg bone. The tensor fascia latae is a small muscle that sits on the outer portion of your hip and inserts into your iliotibial band. The gluteus maximus is the largest and outermost butt muscle. It too inserts into the iliotibial band. The gluteus medius lies underneath the gluteus maximus and the gletus minimus lies underneath the gluteus medius. The piriformis starts at your sacrum and stretches out to your femur.
Tie an elastic band around your ankles such as an exercise band or rubber tubing. Make sure there is resistance with your feet hip-width apart. Start with low resistance and progressively work your way up to heavier resistance. Stand with your hands on your hips and feet hip-width apart. Bend your knees 45 degrees. Keep your knees directly over your ankles. Step out with your right foot. Pause. Step in with your left foot, returning your feet to hip-width. Continue for 20 steps. Repeat on the other side, leading with your left foot. You can buy the elastic bands at any sports store.
Next the standing Side Leg Raises,
Stand with your feet slightly wider than hip-width apart. Turn your right toes out 45 degrees and bed your right knee to 45 degrees. Bring all your body weight into your right leg and come on to the toes of your left foot. Raise your left leg as high as possible. Keep your left hip extended and your left leg straight. Slowly lower your left leg to the floor. Gentle tap your left big toe on the floor, then raise your leg back up. Complete 20 repetitions. Switch and do the other side.
Last the Side Leg Raises
Come to the floor and lie on your right side. Bend your right elbow and place your head in your right palm. Make a straight line from your right elbow to your right heel. Place your left hand on the floor in front of your chest. Slowly lift your left leg into the air as high as you can. Keep your left hip extended and your left leg straight. Pause at the top. Slowly lower your leg down but do not let it touch your right leg. Complete 20 repetitions. Repeat on the other side.
If you google the exercises you should see how to perform them.
One inner thigh exercise I do is from Shaun T's Focus T25. You stand with your feet and knees together, bend your knees in a squat position. Make sure you squeeze your knees together, as if there's a balloon there that you're trying to pop. Then you touch your left hand to the outside of the right foot, then your right hand to the outside of your left foot keeping your back straight. You can do that for a minute.
Another option is doing yoga or pilates. Both are great for inner thigh exercises, especially pilates.