an effective understanding
- a penetration of a barrier like an enemy's defense
- making an essential development
unexpected, remarkable, and essential breakthrough or development, esp. in technology
1918, in a military feeling, from break (v.) + through (adv.). The verbal phrase is attested from c.1400. Indicating "abrupt solution or progress" is from 1930s, in the notion of a fruitful assault.
Highly considerable or dramatic creation or improvement in performance, attained through consistent, focused, and synergic efforts.
One breakthrough is all it will take to change the world.