The definition of m is the thirteenth letter of the English alphabet.(noun)
An example of m is the first letter in the word "martian."
See m in Webster's New World College Dictionary
Origin: see M (sense )noon: a.m., p.m.
Origin: L meridiesnoon: A.M., P.M.
See m in American Heritage Dictionary 4
or Mnoun pl. M's m's or M's also ms or Ms
Origin: M, military classification.
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