‖ rouille|ruj| [Fr., lit. ‘rust’.] Mayonnaise flavoured with pimento or the like. 1951R. Campbell Light on Dark Horse xix. 275 No decent fisherman will eat bouillabaisse without the rouille.1976N. Roberts Face of France ix. 101 A fish soup..a bourride, with a spoonful of rouille stirred into it.