Hierarchy (of decoration)
A system for arranging elements in a series according to formal or functional degrees of importance. A hierarchy can be applied to decorative elements, which may vary in content to include miniatures, title pieces, headpieces, tailpieces, borders, major initials, minor initials, litterae florissae, litterae notabiliores, line fillers, run-over symbols, bas-de-page scenes, and marginalia. Each illuminated manuscript displays its own hierarchy of decoration, whose various elements may contain a number of grades to indicate the relative importance of a section of text or to highlight and differentiate textual divisions.
Michelle Brown, Understanding Illuminated Manuscripts (Malibu, CA: J. Paul Getty Museum in association with the British Library, c1994).