E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Food for show only, and not intended to be eaten except by certain privileged persons. The term is Jewish, and refers to the twelve loaves which the priest showed or exhibited to Jehovah, by placing them week by week on the sanctuary table. At the end of the week, the priest who had been in office was allowed to take them home for his own eating; but no one else was allowed to partake of them.