sta·pes 
(st
āp
ēz)
n. pl. stapes or
sta·pe·des (st
āp
ĭ-d
ēz
′)
The innermost of the three small bones of the middle ear, shaped somewhat like a stirrup. Also called stirrup.
[New Latin stapēs, stapēd-, from Medieval Latin, stirrup, perhaps alteration (influenced by Latin stāre, to stand, and pēs, ped-, foot) of staffa, stapha, of Germanic origin; akin to Old English stæpe, stepe, step.]
sta·pedi·al (stā-pēdē-əl) adj.