Iliotibial is a term that refers to the iliotibial band, which is a thickened tendon-like structure on the outside of the thigh. It runs from the hip joint down towards the knee and helps stabilize the knee joint while also providing some flexibility in the leg. The word "iliotibial" comes from the Latin words for hip (iliacus) and tibia, which is the bone that the band wraps around near the knee.