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Pronounced 'zen-noh-foh-bee-ah', xenophobia is the term used to describe a national disposition towards hatred against another nation or culture. Most often resulting in war between two nations, it has various subdivisions including fascism, nazism, racism, and any other kind of bigotry you care to name.
It is a uniquely human concept, in that there are no recorded instances of xenophobia amongst any other divisions of the animal kingdom eg African Elephants vs Indian Elephants, or Scottish Spiders vs English Spiders.
Curiously, this entirely human state of mental imbalance has led to attempts to include the other divisions of the animal kingdom by naming sporting teams after them eg Buffalo Bulls vs Pennsylvania Pit Bulls1.
1Or some such. American football names can be very confusing to non-followers.