1911 Encyclopædia Britannica/Ditto

DITTO (from the Lat. dictum, something said, Ital. detto, aforesaid), that which has been said before, the same thing. The word is frequently abbreviated into “do.” In accounts, “ditto” is indicated by two dots or a dash under the word or figure that would otherwise be repeated. A “suit of dittos,” a trade or slang phrase, is a suit in which coat, trousers and waistcoat are all of the same material.