The world museums and libraries hold extensive collections of old manuscripts, books, works of applied arts, in the design of which the oriental ornament called the arabesque is used. In this article, the arabesque is examined as a material object that has a symbolic designation and an informational component, that is a document. The author reviews the historical origins of the arabesque, describes its elements, artistic techniques and techniques of the geometric construction from the point of view of the syntactive component. The author focuses on the Arabic calligraphy used in the ornaments, as a significant part of Islamic culture; the development of Arabic writing and various types of handwriting is discussed. The calligraphic inscriptions in the arabesque are considered as a phenomenon of even the higher significance than the image. The author explains the origins of complicated unreadable and abbreviated inscriptions in the ornaments. In total, the classification and document classification criteria developed by G. N. Shvetsova-Vodka were applied to seven diverse ornaments.The study proves that this classification works efficiently and is easy to use: the considered detailed features confirm the correspondence of the arabesque to the term “document”. The article may be of interest to specialists in the field of library science, historians, art historians, religious scholars, artists and designers.