n 1 a  :  either of two muscles arising from the obturator membrane and adjacent bony surfaces: (1) :  OBTURATOR EXTERNUS (2) :  OBTURATOR INTERNUS  b  :  OBTURATOR NERVE  2 a  :  a prosthetic device that closes or blocks up an opening (as a fissure in the palate)  b  :  a device that blocks the opening of an instrument (as a sigmoidoscope) that is being introduced into the body .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.