Word.ws English Dictionary

rubicon

Syllables: ru·bi·con/ˈɹuːbɪkɒn/US/ˈɹubəˌkɑn/

rubicon noun: a limit that when surpassed cannot be returned from, or an action that when taken cannot be reversed.

Noun (1)

rubicon (plural rubicons)

  1. A limit that when surpassed cannot be returned from, or an action that when taken cannot be reversed.
    • Fortunately for England ſhe is yet on the peaceable ſide of the Rubicon; but as the flames once kindled are not alway eaſily extinguiſhed, the hopes of peace are not ſo clear as before the late myſterious diſpute began.1787, [Thomas Paine], “Preface”, in Prospects on the Rubicon: Or, An Investigation into the Causes and Consequences of the Politics to be Agitated at the Meeting of Parliament, London: Printed for...
    • So when friends are lied into distrust of each other, and the rubicon has been passed, either by the death of one, or that the light of truth will not break in upon the mist resting upon the other, [...] at a day too late a discovery arises, and the perpetrators of this fruitless crime, console...1834 June 16, “Interference”, in The Gleaner, 2nd edition, number 7, Boston, Mass.: Published by Joseph S[torer] Hart, […], →OCLC, column 1
  2. Especially in bezique and piquet: a score which, if not achieved by a losing player, increases the player's penalty.
    • The game is called a double, and you score 200 instead of 100 when your adversary does not get 100, which, in technical language, is called crossing the Rubicon.1873 August 1, “Answers to Correspondents. [Piquet.]”, in The Westminster Papers. A Monthly Journal of Chess, Whist, Games of Skill, and the Drama, volume VI, London: W. Kent & Co., […], and W. W....
    • If you are a good way ahead, and particularly in the last hand but one, if you have a chance of winning a Rubicon, you should make a safe discard, with the view of dividing or winning the cards, in order to keep your adversary back. On the other hand, if the score is much against you, and you are...1885, Cavendish [pseudonym; Henry Jones], “Hints to Learners”, in The Laws of Piquet: Edited by “Cavendish” and Adopted by the Portland and Turf Clubs: With a Treatise on the Game, 4th edition...

Verb

rubicon (third-person singular simple present rubicons, present participle rubiconing, simple past and past participle rubiconed)

  1. (transitive) Especially in bezique and piquet: to defeat a player who has not achieved the rubicon.
    • A curious score was made in a game of piquet with one of the ladies. [...] In the fifth hand she made a piquet and capot, scoring 121 to 0, and in the sixth hand, being the minor, she made a repiquet, taking all but the last trick, counting 111 to 3, totalling 270, and rubiconing her opponent at...1902 November, Walter Del Mar, “London to Colombo”, in Around the World through Japan, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., →OCLC, pages 3–4
    • Fleming initiated me into the mysteries of Bézique, and at once set about rubiconing me, [...]1934, J[ohn] Angus Beckett, “The Return Ice-cap Journey”, in Iceland Adventure: The Double Traverse of Vatnajökull by the Cambridge Expedition, London: H. F. & G. Witherby, →OCLC, pages 125–126

Proper noun capitalized: Rubicon

(the) Rubicon

  1. (historical) A small river in northeastern Italy which flowed into the Adriatic Sea marking the boundary between the Roman province of Gaul and the Roman heartland. Its crossing by Julius Caesar in 49 B.C.E. began a civil war.
  2. The same river in the present day, identified with a river previously named Fiumicino.
  3. A locality in the Shire of Murrindindi, central eastern Victoria, Australia.

Noun (2) capitalized: Rubicon

Rubicon (plural Rubicons)

  1. Alternative letter-case form of rubicon (“a limit that when exceeded, or an action that when taken, cannot be reversed; especially in bezique and piquet: a score which, if not achieved by a losing player, increases the player's penalty”).
    • Fortunately for England ſhe is yet on the peaceable ſide of the Rubicon; but as the flames once kindled are not alway eaſily extinguiſhed, the hopes of peace are not ſo clear as before the late myſterious diſpute began.1787, [Thomas Paine], “Preface”, in Prospects on the Rubicon: Or, An Investigation into the Causes and Consequences of the Politics to be Agitated at the Meeting of Parliament, London: Printed for...
    • But, my hearers, there are Rubicons to be passed in our religious and moral course, as well as in our temporal—occasions in the experience of our hearts, which extend their influence so far into the future, that it mainly depends on the decision we then make, and the purposes we then form, whether...1836 January, James M. Mathews, “Sermon CCVIII. Critical Periods in the Sinner’s Life.”, in Austin Dickinson, editor, The American National Preacher: Or Original Monthly Sermons from Living Ministers...

Examples of rubicon in a sentence

  • We are always passing the Rubicon, or being called upon to see somebody else pass it.1853 January–June, “Used-up Classical Allusions”, in The British Journal: A Home, Colonial, and General Magazine, volume III, London: John...
  • It becomes the most final of Rubicons, the most suicidal of bridge-burnings, a leap into an abyss of vaguely dreadful activities,—a fantastic world where people stand on their feet and tie neckties.1908 February, T[homas] Lawrason Riggs, “On Getting Up”, in J. Howland Auchincloss et al., editors, The Yale Literary Magazine: […], volume...
  • Like [Julius] Caesar, individuals often have little trouble pointing to the rubicons in their own lives.1970, Social Action, Boston, Mass.: Pilgrim Press for the Council for Social Action of the Congregational and Christian Churches of...
  • The maintenance of a live cell, the control of its behaviour, its development, its reproduction, and its eventual death, are determined by a series of physical and chemical thresholds, or ‘rubicons’.1991, Anthony K. Campbell, “The Rubicon Hypothesis: A Quantal Framework for Understanding the Molecular Pathway of Cell Activation and...

Synonyms of rubicon

Forms of rubicon

Noun
pluralrubicons
alternative formRubicon
pluralRubicons
Verb
third-person singular presentrubicons
present participlerubiconing
past participlerubiconed
pastrubiconed

Origin of rubicon

The noun is derived from the phrase cross the Rubicon (“to make an irreversible decision or to take an action with consequences”). Julius Caesar’s crossing of the Rubicon, a small river in northeastern Italy, on 10 January 49 B.C.E., indicated his intention to start a civil war with Pompey. Rubicon is derived from Latin Rubicō, Rubicōn (“the Rubicon”), possibly from rubeus (“red, reddish”), from rubeō (“to be red”), ultimately from Proto-Indo-European *h₁rewdʰ- (“red”), an allusion to the colour of the river caused by mud deposits. The verb is derived from the noun.

From Latin Rubicō, Rubicōn (“the Rubicon”), possibly from rubeus (“red, reddish”), from rubeō (“to be red”), ultimately from Proto-Indo-European *h₁rewdʰ- (“red”), an allusion to the colour of the river caused by mud deposits.

Words formed from rubicon

Phrases with rubicon

Questions about rubicon

What does rubicon mean?
Rubicon means a limit that when surpassed cannot be returned from, or an action that when taken cannot be reversed.
How do you use rubicon in a sentence?
We are always passing the Rubicon, or being called upon to see somebody else pass it.
What part of speech is rubicon?
Rubicon can be a noun, a verb or a proper noun.
How do you pronounce rubicon?
Rubicon is pronounced /ˈɹuːbɪkɒn/ (UK).
What is the plural of rubicon?
The plural of rubicon is rubicons.

Words near rubicon in the dictionary

  1. rubicelles
  2. rubicels
  3. rubicene
  4. rubicline
  5. rubicolous
  6. rubicon
  7. rubiconed
  8. rubiconing
  9. rubicons
  10. rubicose
  11. rubicund

Source and license

Adapted from Wiktionary: rubicon (page history and authors); Rubicon (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Pronunciation audio from Wikimedia Commons, each file under its own free license: En-au-rubicon.ogg, LL-Q1860 (eng)-Vealhurl-Rubicon.wav.

Cite this entry: “rubicon.” Word.ws, https://word.ws/rubicon. Based on Wiktionary, CC BY-SA 4.0.