Marks made in the margins of a book or other document. They may be scribbles, comments, glosses (annotations), critiques, doodles, or illuminations.
Scholia are grammatical, critical, or explanatory comments — original or copied from prior commentaries — which are inserted in the margin of the manuscript of ancient authors, as glosses.
Eusebian canons, Eusebian sections or Eusebian apparatus, also known as Ammonian sections, are the system of dividing the four Gospels used between late Antiquity and the Middle Ages. The divisions into chapters and verses used in modern texts date only from the 13th and 16th centuries, respectively.