Real Dictionary

permeate
verb: If an idea, feeling, or attitude permeates a system or permeates society, it affects every part of it or is present throughout it.
verb: If something permeates a place, it spreads throughout it.

permeate in American English
to pass into or through and affect every part of; penetrate and spread through
intransitive verb: to become diffused; penetrate
transitive verb: to pass into or through every part of

permeate in British English
verb: to penetrate or pervade (a substance, area, etc)

permeate in Chemical Engineering
To permeate a membrane, or to permeate through it, means to pass through a membrane by dissolving and then diffusing in it.