Refers to the culture and styles associated with the Celts, an early Indo-European people who spread over Europe, from the British Isles and northern Spain to east of Transylvania, the Black Sea coasts, and Galatia in Anatolia, from the second millennium BCE to the first century BCE. Elements of the style persisted for centuries in southern Scandinavia and the post-Roman British Isles. It is characterized by a reference to the art of ancient Italy, Greece, and the East, combined in a new and individual style that includes a strong sense of form and structure, stylized plant, animal, and human forms, a balance of voids and ornament, vigorous vitality, and contrasts of texture.

Fonte: Art & Architecture Thesaurus 

http://vocab.getty.edu/page/aat/300019470