Permeation
Soaking, Osmosis
Immersed to the point where it's transparent, because it's so soaked... that is total permeation and soaking and osmosis.
しんとう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
こちらの化粧水は、お肌の奥深くまで浸透するということで、すごく人気が出てきています。
This face lotion is getting really popular because it deeply permeates into the skin.