In computer science hash could be short for one of the following:
Hash function, which is a specialized type of function used to convert data with a large range to a smaller range. (In computer science jargon "hash" can be used as a noun to refer to a hash function or as a verb meaning the application of such a function)
Hash (food) - A food consisting of diced meat and potatoes.
An informal running race in which "hashers" chase a "rabbit" (lead runner) on an improvised course. This usage is evidenced in a number of (particularly British) athletics clubs such as the Hash House Harriers.
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