In Ruby, why is the accumulator called memo in the inject/reduce methods?

ruby

Solution

`"memo"` means in memory,that inject uses throughout its full iteration to hold the intermediate object state,to use it for its next iteration.

Problem

Out of curiosity, why is the accumulator called memo in the inject/reduce methods? Is there some context/history behind its naming? Does it actually mean "memo" or does memo stand for something? http://ruby-doc.org/core-2.0/Enumerable.html#method-i-inject http://ruby-doc.org/core-2.0/Enumerable.html#method-i-reduce

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