Malleolus, Latin for little hammer. Vesalius, in the 16th century, was the first to use the term for the rounded, bony processes on the distal fibula (the lateral malleolus) and tibia (the medial malleolus), often referred to as the "ankle bones" in casual conversation.
That Vaselius called these relatively large processes "little hammers" is a bit ironic, considering that one of the smallest bones in the body, the malleus of the middle ear, was given the non-diminutive Latin name for hammer (probably named by the Italian anatomist Alessandro Achillini, 1463-1512). See malleus for a discussion of Vaselius's inspiration for coining the term malleolus.
30% of ankle fractures involve the malleoli, usually the lateral.