EMBOISMUS, ἔμβολισμός, in Chronology, signifies intercalation. The word is formed from ἔμβολος, 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, that is, they added a thirteenth lunar month every two or three years, which additional month they called embolimæus, ἔμβολαιος, because inserted or intercalated.