Metasploit
The Metasploit Framework is a development platform for developing and using security tools and exploits.
Metasploit Meterpreter
The Meterpreter is a payload within the Metasploit Framework which provides control over an exploited target system, running as a DLL loaded inside of any process on a target machine.
Metasploit msfpayload
The msfpayload tool is component of the Metasploit Framework which allows the user to generate a standalone version of any payload within the framework. Payloads can be generated in a variety of formats including executable, Perl script, and raw shellcode.