The ArtLex Art Dictionary has “definitions for more than 3,600 terms used in discussing visual culture, along with thousands of supporting images, pronunciation notes, great quotations and cross-references.” A sample entry:
Rayonism – A type of abstract or semi-abstract painting characterized by the fragmentation of forms into masses of slanting lines. It was practised from 1912-1914 by Natalya S. Goncharova (Russian-French, 1881-1962), Mikhail Larionov (Russian-French, 1881-1964), and a few other Russian painters. Larionov’s manifesto on Rayonism stated that it is a synthesis of Cubism, Futurism, and Orphism.” Aspects of each of those isms can indeed be seen in Rayonist paintings — Cubism’s breaking up of forms, Futurism’s movement of forms, and Orphism’s rich color. In addition, the Rayonists expounded a theory that objects emitted invisible rays which the painters could manipulate to their own purposes. “The rays which emanate from the objects and cross over one another give rise to rayonist forms. The artist transforms these by bending them to his desire for aesthetic expression.” Goncharova and Larionov often applied the paint in their Rayonist works with palette knives.
Also called “Rayonnism,” “Rayism,” and, in Russian, “Luchism.”
All the significant terms are linked to other entries, and the text is followed by reproductions of five Rayonist paintings. A very useful site. (Via wood s lot.)