ἐμβολισμός, in chronology, signifies "intercalation." The word is formed of ἐμβάλλειν, "to insert."

As the Greeks made use of the lunar year, which is only 354 days, in order to bring it to the solar, which is 365 days, they had every two or three years an embolism, i.e., they added a 13th lunar month every two or three years, which additional month they called embolismos, ἐμβολισμός, because inserted, or intercalated.