rubicon

• POS: Noun
• HYPHEN: Ru=bi=con

CIDE DICTIONARY

rubicon, n. 

 A small river which separated Italy from Cisalpine Gaul, the province alloted to Julius Cæsar.  [1913 Webster]
" By leading an army across this river, contrary to the prohibition of the civil government at Rome, Cæsar precipitated the civil war which resulted in the death of Pompey and the overthrow of the senate; hence, the phrase to pass or cross the Rubicon signifies to take the decisive step by which one is committed to a hazardous enterprise from which there is no retreat."  [1913 Webster]

OXFORD DICTIONARY

rubicon, n.
1 a boundary which once crossed betokens irrevocable commitment; a point of no return.
2 (rubicon) the act of winning a game in piquet before an opponent has scored 100.

Etymology

the ancient name of a stream forming the boundary of Julius Caesar's province and crossed by him in 49 BC as the start of a war with Pompey

ROGET THESAURUS

rubicon

Limit

N limit, boundary, bounds, confine, enclave, term, bourn, verge, curbstone, but, pale, reservation, termination, terminus, stint, frontier, precinct, marches, backwoods, boundary line, landmark, line of demarcation, line of circumvallation, pillars of Hercules, Rubicon, turning point, ne plus ultra, sluice, floodgate, definite, conterminate, conterminable, terminal, frontier, bordering, thus far, thus far and no further, stick to the reservation, go beyond the pale, Special.