Is it farther or further?
late 14c., from Old French porosité, from Medieval Latin porositas, from porus (see pore (n.)).
porosity po·ros·i·ty (pə-rŏs'ĭ-tē, pô-)n.
The state or property of being porous.
A structure or part that is porous.
A cavity or perforation.
The condition of being porous.
The ratio of the volume of all the pores in a material to the volume of the whole.