Definitions of rallying:

• noun:   the act of mobilizing for a common purpose

  Example: "The bell was a signal for the rallying of the whole neighborhood"

• noun:   the feat of mustering strength for a renewed effort

  Example: "He feared the rallying of their troops for a counterattack"

• adjective:   rousing or recalling to unity and renewed effort

  Example: "A rallying cry"