Noun(1) the boundary in ancient times between Italy and Gaul; Caesar's crossing it with his army in 49 BC was an act of war(2) a line that when crossed permits of no return and typically results in irrevocable commitment(3) the boundary in ancient times between Italy and Gaul(4) Caesar's crossing it with his army in 49 BC was an act of war
Noun(1) the boundary in ancient times between Italy and Gaul; Caesar's crossing it with his army in 49 BC was an act of war(2) a line that when crossed permits of no return and typically results in irrevocable commitment(3) the boundary in ancient times between Italy and Gaul(4) Caesar's crossing it with his army in 49 BC was an act of war