“This is not a course in philosophical speculation, nor is it concerned with precise terminology. It is concerned only with the Atonement, or the correction of perception. The means of the Atonement is forgiveness. (C-in.1)”
This quotation explains why there are differing definitions for Atonement in A Course in Miracles. Jesus is not concerned with specifics, carefully equating similar terms whenever he can.
Here Jesus’s definition for Atonement is the “correction of perception.” We know that perception is what we use in this world to find our way about. It is not knowledge, which comes from God. This perception is made by projection from within each individual.
Since the ego still rules very many of us, it is the ego that projects the perceptions that we make. And it is this perception that needs correction.
The means of correction of perception is forgiveness. In particular, we reach out to our significant others, our brother, and in the forgiveness that we extend, we find love.
What better formula could there be for a new world to be seen by corrected perception?