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A 'Mustard Coincidence' occurs when you hear the same subject repeated from differing sources in close timing multiple times with no obvious alternative explanation.
A One of your friends talks at length about mustard while eating mustard.

Later in the day you see a mustard commercial on TV

You then see a man buying inordinate amounts of mustard at the supermarket.

This is the Mustard Coincidence.
by c--b April 24, 2010