According to the 'Gould Medical Dictionary' 3rd Ed., the plural of pelvis is pelves. Pronounced pel.veez. It applies to other anatomical features besides the bony structure referred to. For example, the pelvis if the kidney. The primary definition is as a basin or basin shaped cavity. Cheers, Alan brushes2@juno.com 92 High Street Mystic, CT. 06355 (860) 572-1717