The Collaborative International Dictionary of English v.0.48:

Cotyla \Cot"y*la\ (k?t"?-l?), Cotyle \Cot"y*le\ (k?t"?-l?), n.
   [Gr. ??? anything hollow, cup of a joint, small meassure: cf.
   L. cotyla a measure.] (Anat.)
   A cuplike cavity or organ. Same as Acetabulum.
   [1913 Webster]