From HomoExcelsior

1. To go back; move backward. 2. To return to a previous, usually worse or less developed state. 3. To have a tendency to approach or go back to a statistical mean. 4. To induce a state of regression in. 5. The act of going or coming back; return. 6. Passage back; reentry. 7. The act of reasoning backward from an effect to a cause.

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