From HomoExcelsior

1. A structure, such as a fence, built to bar passage. 2. obstacle 3. A physical or biological factor that limits the migration, interbreeding, or free movement of individuals or populations. 4. A boundary or limit. 5. Something that separates or holds apart. 6. A movable gate that keeps racehorses in line before the start of a race. 7. The palisades or fences enclosing the lists of a medieval tournament. Often used in the plural. 8. An ice barrier.

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