n.
Pronunciation: ' rü-bi- ˌ kän
Function: noun
Etymology: Latin Rubicon-, Rubico, river of northern Italy forming part of the boundary between Cisalpine Gaul and Italy whose crossing by Julius Caesar in 49 B.C. was regarded by the Senate as an act of war
Date: 1626
: a bounding or limiting line especially : one that when crossed commits a person irrevocably