The arabesque is a form of artistic decoration consisting of "surface decorations based on rhythmic linear patterns of scrolling and interlacing foliage, tendrils" or plain lines, often combined with other elements. Another definition is "Foliate ornament, used in the Islamic world, typically using leaves, derived from stylised half-palmettes, which were combined with spiralling stems". It usually consists of a single design which can be 'tiled' or seamlessly repeated as many times as desired. Within the very wide range of Eurasian decorative art that includes motifs matching this basic definition, the term "arabesque" is used consistently as a technical term by art historians to describe only elements of the decoration found in two phases: Islamic art from about the 9th century onwards, and European decorative art from the Renaissance onwards. Interlace and scroll decoration are terms used for most other types of similar patterns.

Arabesques are a fundamental element of Islamic art but they develop what was already a long tradition by the coming of Islam. The past and current usage of the term in respect of European art is confused and inconsistent. Some Western arabesques derive from Islamic art, but others are closely based on ancient Roman decorations. In the West they are essentially found in the decorative arts, but because of the generally non-figurative nature of Islamic art, arabesque decoration is there often a very prominent element in the most significant works, and plays a large part in the decoration of architecture.

Claims are often made regarding the theological significance of the arabesque and its origin in a specifically Islamic view of the world; however, these are without support from written historical sources since, like most medieval cultures, the Islamic world has not left us documentation of their intentions in using the decorative motifs they did. At the popular level such theories often appear uninformed as to the wider context of the arabesque. In similar fashion, proposed connections between the arabesque and Arabic knowledge of geometry remains a subject of debate; not all art historians are persuaded that such knowledge had reached, or was needed by, those creating arabesque designs, although in certain cases there is evidence that such a connection did exist. The case for a connection with Islamic mathematics is much stronger for the development of the geometric patterns with which arabesques are often combined in art. Geometric decoration often uses patterns that are made up of straight lines and regular angles that somewhat resemble curvilinear arabesque patterns; the extent to which these too are described as arabesque varies between different writers.