Rubicon(noun)

the boundary in ancient times between Italy and Gaul; Caesar's crossing it with his army in 49 BC was an act of war

Rubicon, point of no return(noun)

a line that when crossed permits of no return and typically results in irrevocable commitment

Rubicon(ProperNoun)

An ancient Latin name for a small river in northern Italy which flows into the Adriatic Sea. It marked the boundary between the Roman province of Gaul and the Roman heartland. Its crossing by Julius Caesar in 49 BC began a civil war.

rubicon(Noun)

A limit that when exceeded, or an action that when taken, cannot be reversed.

Rubicon(noun)

a small river which separated Italy from Cisalpine Gaul, the province alloted to Julius Caesar

Rubicon

a famous river of Italy, associated with Julius Cæsar, now identified with the modern Fiumecino, a mountain torrent which springs out of the eastern flank of the Apennines and enters the Adriatic N. of Ariminum; marked the boundary line between Roman Italy and Cisalpine Gaul, a province administered by Cæsar; when he crossed it in 49 B.C. it was tantamount to a declaration of war against the Republic, hence the expression "to cross the Rubicon" is applied to the decisive step in any adventurous undertaking.