It is the means by which God is not separate from us. It seems to me that the idea of "created grace" keeps God so separate from us that ultimately we cannot have communion with Him.
Thinking of it this way, before Adam sinned, humanity was capable of incorruption due to union with God. In fact, incorruption is not a natural human attribute, but a grace from God, since only God is incorruptible. By man's disobedience, man lost such grace, and naturally lived and died like all other animals.
One can also consider grace as the "presence of God," that divine, uncreated presence. The Theotokos St. Mary is "full of grace" for having bore for us the Eternal Logos Incarnate. In one of our Theotokias (Coptic), we sing to the Virgin "Hail to you oh incorrupt vessel of the divinity," where we are reminded to "Praise God in all His saints" and that we too can be vessels of the Divine Grace.