Penetration refers to entering or making your way through something. It's also a deep insight.
When something penetrates, it’s going through something else, so penetration is an example of this happening. You could talk about the penetration of a jacket by a knife, or the penetration of a fortress by an army. When a basketball team pierces the other team's defenses, it's called penetration. Also, in-depth perception or insight is called penetration. Just like physical penetration goes deep into something, mental penetration implies deep understanding of an idea or situation.