rallying point

noun2

1. •
   A designated area for troops to concentrate upon; a sign marking such an area.

   • At last, 'Ali, perceiving that her camel was the rallying-point of the enemy, sent one of his captains to hamstring, and thus disable it. With a loud cry the animal fell to the ground. — 1924
2. •
   (figurative) A cause, symbol, or a place that may unite a fragmented group or persons opposing each over in other matters.

   • The proposition that James had ceased to be King had been the rallying point of the two parties which had made up the majority. But from that point their path diverged. — 1848