permeation
noun
- penetration of a permeate (such as a liquid, gas, or vapor) through a solid
Wiktionary
Pronunciation: /ˌpɜːmiˈeɪʃən/ / /ˌpɝmiˈeɪ̯ʃən/ / /ˌpɜːmiˈæɪʃən/
noun
- The movement of a fluid through a porous or permeable solid.
- The spreading of something (especially something malignant) through the body via blood vessels etc.