3 synonyms found - words and phrases with similiar meaning. 
Definition
                             
                             
                        
                     
                                        
                                                    noun
                            
                                                                    - a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
- a device for showing the operating condition of some system
- a signal for attracting attention
- (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction