Why is the ninth month called September?
early 15c., from Late Latin permeabilis "that can be passed through, passable," from Latin permeare "to pass through, go over," from per- "through" (see per) + meare "to pass," from PIE root *mei- "to change" (see mutable). Related: Permeably.
permeable per·me·a·ble (pûr'mē-ə-bəl)adj. That can be permeated or penetrated, especially by liquids or gases.