permeance / permeants [ˈpɜrmi:ən(t)s]
permeance – n. – 1. the ability to infuse or pass through something; 2. the degree to which a liquid or gas diffuses into a solid; 3. Electronics one of the physical parameters of an magnetic circuit, representing the readiness with which magnetic flux may be established
permeants – n. pl. of permeant – 1. Ecology animal influents that range widely within different ecological systems; 2. Physiology a molecule or ion that passes easily through a cell membrane