When you choose Evaluation ► Kernel Configuration Options, a dialog box lists the kernel connections already defined. "Local" is the default connection to the Mathematica kernel on your local machine.
To define a new kernel, choose Evaluation ► Kernel Configuration Options and click Add. The configuration dialog box will open to let you define the new connection. Fill in the kernel name at the top of the dialog box and choose whether to launch the kernel on the local computer or on a remote computer. Give the name of the kernel program. On Macintosh or Windows, the name is typically "MathKernel"; on Unix systems, the name is typically "math", the shell script that runs the Mathematica kernel. Click OK to save the kernel connection.
When Append name to In/Out prompts in the Kernel Properties dialog is checked, the name of the kernel connection is appended to cell labels generated during that connection.
The kernel names that you define here are shown throughout the front end whenever you have a choice of kernels.