A word spoken by the members of Seele in ep.26, when Geo-Front reverted itself back into the "Black Moon" i.e. the Egg of Lilith. "Misogi" originally means a religious ceremony in which body is cleansed through bath in water.
As an extension it means any method used to purify or sanctify a certain object.
While there is a theory that the etymology of ADAM, the ancestor of all human, is red or earth, its link with the "Red Earth" is unclear.