Definition of Essoin
v. In old English practice, to present or offer an excuse for not appearing in court on an appointed day in obedience to a summons; to cast an essoin. This was anciently done by a person whom the party sent for that purpose, called an “essoiner.”
n. In old English law, an excuse for not appearing in court at the return of the process. Presentation of such excuse. Essoin was not now allowed at all in personal actions. 3 Bl.Comm. 278, note.
That's the definition of Essoin in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.