The Collaborative International Dictionary
                    Midfeather
                    
                        
                
                                                                    Midfeather \Mid"feath`er\, n.
- (Steam Boilers) A vertical water space in a fire box or combustion chamber. 
- (Mining) A support for the center of a tunnel. 
Wiktionary
                    midfeather
                    
                        
                
                                                                    n. 1 A vertical water space in a firebox or combustion chamber within a steam boiler. 2 (context mining English) A support for the centre of a tunnel.
Usage examples of "midfeather".
A telltale tickle at the edge of my mind pushed me back behind a towering midfeather which held up the groined ceiling.