An advance through and past enemy lines.
The penetration of the opposition's defence.
Any major progress; such as a great innovation or discovery that overcomes a significant obstacle.
The penetration of a separating wall or the remaining distance to an adjacent hollow (a crosscut in mining) or between two parts of a tunnel build from both ends; knockthrough.
Involving the contraction of a disease by a person with a decreased susceptibility, such as a person who has been vaccinated to help prevent that disease.
Characterized by major progress or overcoming some obstacle.
The emergence or one or more symptoms of a condition despite medication or other medical treatment.
Something that guides or marks the way along a figurative journey; a temporary stopping point.
A sign or other marker that indicates the way along a road or trail.