Grace, Latin gratia, is the favour and life of God given freely, not earned. Augustine made it central to Western theology against Pelagius; the mystics describe the higher stages of prayer as grace received, not achieved. The relation between grace and human effort is a question every tradition faces.
Grace
God’s free, unmerited gift of love and help, by which the soul is turned, healed and drawn to union.
Also: gratia, charis