Rubicon /ˈruːbɪˌkɑːn/ noun Learner's definition of RUBICON
the Rubicon
: a limit or point that you reach when the results of your actions cannot be changed（无法走回头路的）界限，界线 ◊ This word comes from the name of a stream that separated Gaul from Italy. In 49 B.C., Julius Caesar started a war by illegally marching his army across the Rubicon and into Italy.此词源自意大利与高卢的界河鲁比肯河。公元前49年，尤利乌斯·凯撒违规率军越过鲁比肯河进入意大利，发动了战争。