Sentence:  The late R. G. Collingwood , a philosopher whose work has proved helpful to many students of literature , <WSD>once</WSD> wrote `` We are all , though many of us are snobbish enough to wish to deny it , in far closer sympathy with the art of the music-hall and picture-palace than with Chaucer and Cimabue , or even Shakespeare and Titian . 
Meaning of the word marked with <WSD> tags:  on one occasion