The act of counting or numbering things together as a group.
From Latin connumeratio, derived from connumerare (to count together). This is the noun form corresponding to the verb connumerate, following the Latin pattern of -tion suffixes.
Medieval scholars used words like this to describe mathematical operations, and you can see the DNA of this word in 'enumeration'—it's like the old English kept the fancy version but forgot the 'con-' part meant 'together'.
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