Biblioclasty: The act of book-breaking or -tearing. While usually reviled (especially within the orbit of old or rare books), the action can be undertaken for more complex and altruistic reasons than censorship, theft, financial gain, or wanton destruction. Otto Ege's biblioclasty, for example, was intimately tied to his advocacy of popular art education.
Bifolio: A piece of paper or vellum folded once, creating two folios or leaves. It is not uncommon to find a detached leaf from a medieval manuscript with traces of its paired leaf (the other half of its bifolio) still visible along the fold.
Folio: A piece of paper or vellum; a single page in a book. When detached from a book, a folio is often called a leaf. In pre-modern practice folios are often only numbered on one side; modern page numbering would thus result in twice as many pages as folios in the same book. The term is also used in bookbinding to refer to a large paper size, which can cause some confusion.
Gloss: A comment or definition written in a book. It is usually visually subordinated to the main text of a page (i.e., in the margin or between the lines), and may have been part of the planned design of the page or have been added later.
Illumination: The use or presence of gold on a manuscript page. There are many recipes and application techniques for the material, but when successfully applied it allows light to reflect off the page (hence its symbolic value for reading and understanding).
Miniature: A drawn or painted image in a manuscript, often depicting a scene from the text or providing visual commentary on it. Miniatures are often skillfully drawn and beautifully colored, but they need not be small--a picture that takes up an entire page in a manuscript is still called a miniature.
Parchment: See Vellum.
Provenance: The places a book has traveled to and the owners it has had since the time it was made. Provenance is a key component of both academic manuscript studies and the rare book trade; Otto Ege is now a notable part of the provenance of the books he owned during his lifetime.
Recto: The front side of a page; what you see on the right-hand side of an open book. (See also Verso.)
Rubrication: From the Latin rubricare, "to color red," this is any text written in a different color than the main text. Red is by far the most common, but one can find blue or green "rubrications."
Scribe: A person who physically writes down a text. Throughout the Middle Ages it can refer to any of a number of activities, from the conservative (i.e, the exact copying of a Latin Bible) to the free (the spontaneous transformation of French prose into English poetry). In the case of the Ege leaves, which mostly come from liturgical books, scribe nearly always connotes a literate male who belonged to one of the Christian religious orders.
Vellum: The chief writing surface of the Middle Ages, made from animal skin (a sheep, goat, or cow). The animal's hair is scraped from the skin, and the dermis is carefully stretched and cleaned to provide a large, smooth surface which can then be folded and cut. While some experts observe a technical distinction between vellum and parchment, the terms are in general practice interchangeable.
Verso: The back side of a page; what you see on the left-hand side of an open book. (See also Recto.)