breakthrough

• POS: Noun
• HYPHEN: break=through

CIDE DICTIONARY

breakthrough, n. 

•  a productive insight.  [WordNet 1.5]
•  a sudden change of situation, such as making an important discovery, that permits further rapid advances toward a goal.  [WordNet 1.5]
•  a penetration of an enemy's defense in depth and strength.  [WordNet 1.5]

OXFORD DICTIONARY

breakthrough, n.
1 a major advance or discovery.
2 an act of breaking through an obstacle etc.

THESAURUS

breakthrough

aggravated assault, aggression, amphibious attack, armed assault, assailing, assailment, assault, attack, avant-propos, banzai attack, blitz, blitzkrieg, boost, charge, coinage, counterattack, counteroffensive, coup de main, crippling attack, dead set at, descent on, discovery, diversion, diversionary attack, drive, exordium, flank attack, foreword, front matter, frontal attack, frontispiece, gas attack, head-on attack, hike, increase, infiltration, innovation, introduction, invention, leap, lightning attack, lightning war, mass attack, megadeath, mugging, neologism, new phase, novelty, offense, offensive, onset, onslaught, overkill, overture, panzer warfare, postulate, preamble, preface, prefix, prefixture, preliminary, prelude, premise, presupposition, proem, prolegomena, prolegomenon, prolepsis, prologue, protasis, push, run against, run at, rush, sally, shock tactics, sortie, strike, unprovoked assault, upgrade, verse, voluntary, wax