What could be a knot on the ankle mean ?

Swollen: A knot on the ankle could be from swelling or from a hematoma (like a bruise) in the area. Other possibilities are swollen muscle bellies (edb) or a soft tissue growth (usually benign). Good luck.

Knot on the ankle: Without a better description difficult to say. It could be a tendon problem, a ganglion cyst, a soft tissue growth, a bone spur or many other things. I would see your podiatrist to make sure it is nothing serious. Good luck.

Many Possibilities : First need some history, what type of trauma caused it. It could be so many things to fracture to soft tissue injury and everything in between. Please provide details like did yo get an x-ray or MRI etc...