noun
Rubicon
ROO-bih-kon
noun
1
A point of no return — a decision or action that can't be undone once taken.
"Signing the contract meant crossing the Rubicon; there was no backing out now."
"Quitting his stable job to start the business felt like crossing a personal Rubicon."
2
In card games such as piquet and bezique, a minimum score a losing player must reach to avoid a much heavier penalty.
"She failed to reach the rubicon, so her loss counted double."
How to Use Rubicon
Learner’s notesIn plain EnglishA line that, once crossed, can't be uncrossed — the moment a decision becomes irreversible.
Memory tip
Almost always used in the phrase "cross the Rubicon," even outside card games.
Trace the full origin ↓
Common pairings
cross the Rubicon
reach the rubicon
Word Forms
rubiconed past tense, rubicons plural, rubicons singular
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Signing the contract meant crossing the _____; there was no backing out now.
Etymology
From the Rubicon, a small river in northern Italy that Julius Caesar crossed with his army in 49 BCE, an act that made civil war against Rome inevitable — giving us the phrase "crossing the Rubicon."