Source : Free On-Line Dictionary of Computing

Java Run-Time Environment
     
         (JRE) The part of the {Java Development Kit}
        required to run Java programs.  The JRE consists of the {Java
        Virtual Machine}, the {Java} platform core {classes} and
        supporting files.  It does not include the compiler, debugger
        or other tools present in the JDK.  The JRE is the smallest
        set of executables and files that constitute the standard Java
        platform.
     
        (1998-11-30)