penetration

n. /ˌpen.əˈtreɪ.ʃən/ C1

穿透；进入；渗透

The movement of something into or through an area.

仙境例句

The light's penetration into the deep sea was poor, so the school was always rather dark.

阳光很难穿透深深的海水，所以学校里总是暗暗的。