'breakthrough' definitions:

Definition of 'breakthrough'

(from WordNet)
noun
A productive insight [syn: discovery, breakthrough, find]
noun
Making an important discovery
noun
A penetration of a barrier such as an enemy's defense

Definition of 'breakthrough'

From: GCIDE
  • breakthrough \break"through`\ n.
  • 1. a productive insight.
  • Syn: discovery, find. [WordNet 1.5]
  • 2. a sudden change of situation, such as making an important discovery, that permits further rapid advances toward a goal. [WordNet 1.5 +PJC]
  • 3. (Mil.) a penetration of an enemy's defense in depth and strength. [WordNet 1.5] Breakup

Synonyms of 'breakthrough'

From: Moby Thesaurus