The verb extend can have several related meanings, including thrust out, continue, broaden, expand, unfold, span, or increase in scope.
Extend, as a verb, is used in many ways. You extend (hold out) your hand when you offer to shake. You extend (push forward) a deadline when you add a few days to it. Your belly might extend (broaden) after a holiday dinner. A telescope extends (expands) your range of vision. If the list of definitions for extend were infinite, you could extend (add to) that list forever and ever. But your patience might not extend that far.