These commands move point or set up the region based on top-level major definitions, also called “defuns”.
beginning-of-defun‘C-M-a’
Move to beginning of current or preceding defun.
With a negative argument −N moves forward N times to the next beginning of a defun.
end-of-defun‘C-M-e’
Move to end of current or following defun.
With a negative argument moves back to an end of a defun.
mark-defun‘C-M-h’
Put region around whole current or following defun.
This is the easiest way to get ready to kill the defun in order to move it to a different place in the file. If the defun is directly preceded by comments (with no intervening blank lines), they are marked, too.