sa·cro·il·i·ac
                    
                                                                                                              
                                                                                                                                  ˌsa-krō-ˈi-lē-ˌak 
                                                                                                                                  ˌsā- 
                                                      
                                                          
            
                                
              
          
                                                      : of, relating to, or being the region of the joint between the sacrum and ilium                                      
              
                             
sacroiliac pain
                         
                
                    
                                
              
          
                                                      : the sacroiliac region                                      
                
                                
            also                
          
                                                      : its firm fibrous cartilage                                      
            
            Love words? Need even more definitions?
  
  Merriam-Webster unabridged




Share