Means an insertion, addition or interpretation. Article gives two specific uses of this word in the language of the Church
Embolism (Greek: embolismos, from the verb, emballein, “to throw in”), an insertion, addition, interpretation. The word has two specific uses in the language of the Church:
I. The prayer which, in the Mass, is inserted between the Our Father and the Fraction of the Bread: “Libera nos, quaesumus, Domine, ab omnibus malis”, etc. It is an interpretation of the last petition. The embolism may date back to the first centuries, since, under various forms, it is found in all the Occidental and in a great many Oriental, particularly Syrian, Liturgies. The Greek Liturgies of St. Basil and St. John Chrysostom, however, do not contain it. In the Mozarabic Rite this prayer is very beautiful and is recited not only in the Mass, but also after the Our Father at Lauds and Vespers. The Roman Church connects with it a petition for peace in which she inserts the names of the Mother of God, Sts. Peter and Paul, and St. Andrew. The name of St. Andrew is found in the Gelasian Sacramentary, so that its insertion in the Embolismus would seem to have been anterior to the time of St. Gregory. During the Middle Ages the provincial churches and religious orders added the names of other saints, their founders, patrons, etc., according to the discretion of the celebrant (see Micrologus)
II. In the calendar this term signifies the difference of days between the lunar year of only 354 days and the solar year of 365.2922 days. In the Alexandrian lunar cycle of 19 years, therefore, seven months were added, one each in the second, fifth, eighth, eleventh, thirteenth, sixteenth, and nineteenth (the embolistic) years. Each embolistic year had 13 lunar months, or 384 days. The lunar calendar was called Dionysian, because Dionysius Exiguus, in the sixth century, recommended the introduction of the Alexandrian Easter cycle of 19 years and computed it for 95 years in advance.
F. G. HOLWECK