a movement into or through something or someone

Sunscreens can help reduce the penetration of ultraviolet rays into the skin. 防晒霜可以减少紫外线穿透皮肤。

The company is trying to increase its penetration of the market. 该公司正在努力扩大其市场份额。

the act of putting your penis or another object into someone else's body as a sexual act

someone's ability to understand quickly and well