E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
il de Buf (L).
A large reception-room (salle) in the palace of Versailles, lighted by round windows so called. The ceiling, decorated by Van der Meulen, contained likenesses of the children of Louis XIV, (seventeenth and eighteenth centuries).
Les Fastes de lil de Buf. The annals of the courtiers of the Grand Monarque; anecdotes of courtiers generally. The il de buf is the round window seen in entresols, etc. The ante-room where courtiers waited at the royal chamber of Versailles had these ox-eye windows, and hence they were called by this name.