Target Rule : A target rule is a rule that takes all the files that match the file extensions and produces output files that ...

Target Rule : A target rule is a rule that takes all the files that match the file extensions and produces output files that are not dependent on the input file names (such as the linker which operates on all .obj files and produces a single executable).  This property depends on the Outputs property (if the Outputs property does not contain input specific macros, then the rule is considered to be a target rule).  Target rules are required to support file batching.