embolism

noun

1. An obstruction or occlusion of a blood vessel by an embolus, that is by a blood clot, air bubble or other matter that has been transported by the blood stream.
2. The insertion or intercalation of days into the calendar in order to correct the error arising from the difference between the civil year and the solar year.

   “Authorities differ as to the manner in which the Arabs practised embolism: some say, they added a month to every third year; others, that they intercalated seven months in a period of nineteen years ; and others, nine months in twenty-four years.”

3. An intercalated prayer for deliverance from evil coming after the Lord's Prayer.
4. The variable body of a liturgical preface, between the protocol and eschatocol, typically stating the motive for worship on a given day.