The Collaborative International Dictionary
                    Subduplicate
                    
                        
                
                                                                                        
                            Subduplicate \Sub*du"pli*cate\,
- 
(Math.) Expressed by the square root; -- said of ratios.
Subduplicate ratio, the ratio of the square roots, or the square root of a ratio; thus, the subduplicate ratio of a to b is [root]a to [root]b, or [root]a/
 
Wiktionary
                    subduplicate
                    
                        
                
                                                                    a. (context mathematics English) Expressed by the square root; said of ratios.