What is "letters of horning"

Horning \Horn"ing\, n. Appearance of the moon when increasing, or in the form of a crescent.
--J. Gregory.

Letters of horning (Scots Law), the process or authority by which a person, directed by the decree of a court of justice to pay or perform anything, is ordered to comply therewith.
--Mozley & W.

n. (context legal Scotland English) The process or authority by which a person, directed by the decree of a court of justice to pay or perform anything, is ordered to comply.

Letters of horning (Scots law): a document (i.e., letters) issued by civil authorities that publicly denounce a person as a rebel. The document was issued against persons who had not paid their debts.

Historically, the documents would be announced by three blasts of a horn, and the documents themselves came to be known as "letters of horning". A person who was denounced in these documents was described as having been "put to the horn". <!--