What is the origin of enumerate?

Enumerate “to ascertain the number of” comes from the Latin verb ēnumerāre “to count up,” equivalent to the element ē- “out of, from” and the noun numerus “number.” Both enumerate and number come from Latin numerus, but how did that stray b appear in number? As Latin evolved into French, the unstressed e in numerus was slowly lost in a process called syncope; to compare, in English, note how we pronounce the adjective every as “ev’ry.” Because the consonant cluster -mr- was a bit awkward to say, though a pattern called excrescence, the consonant b was inserted between the two letters, producing Old French nombre—much like how hamster and something in English are often pronounced as “hampster” and “sump-thing.” While number passed into English by way of French and therefore featured these two sound shifts, enumerate was borrowed directly from Latin with minimal changes. Enumerate was first recorded in English in the 1640s.