Rhubarb, Rhubarb Words A definition of rhubarb – the noun – isĀ meaningless background noise. This meaning is attributed to the mid 19th century practice of the theater company of Charles Kean at the Princess Theater, London. In crowd scenes actors repeated the word “rhubarb” to mimic the sound of indistinct conversation. Rhubarb was chosen because it has no harsh-sounding…