Also see definition of "Mansion" in Word Study
MANSION [isbe]
MANSION - man'-shun (mone, "abode"): In Jn 14:2, the word is used in the plural: "In my Father's house are many mansions," the Revised Version margin "abiding places." The ideas conveyed are those of abundance of room, and permanence of habitation, in the heavenly world.
Also see definition of "Mansion" in Word Study