Ultimo
Pronunciation : Ul"ti*mo.
Etymology : [L. ultimo (mense) in the last month.]
Definition : Defn: In the month immediately preceding the present; as, on the 1st ultimo; -- usually abbreviated to ult. Cf. Proximo.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder