From HomoExcelsior

1. apparent horizon 2. The sensible horizon. 3. The celestial horizon. 4. The limit of the theoretically possible universe. 5. The range of one's knowledge, experience, or interest. 6. A specific position in a stratigraphic column, such as the location of one or more fossils, that serves to identify the stratum with a particular period. 7. A specific layer of soil or subsoil in a vertical cross section of land.

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