a gap or breach made in a defensive line

breakthrough; path-breaking; groundbreaking

a point of penetration where a barrier is broken, especially in a military or problem-solving context

to achieve something for the first time where there were previously no results; to break a record from zero

To overcome a bottleneck or key obstacle in order to reach a new stage of development; to break through a deadlock.

a first-ever breakthrough; to achieve something for the first time from a starting point of nothing

A significant improvement or a major change that breaks through current limitations; a large-scale advancement or transformation.