The very first pancake that is cooked. Typically turns out to be the worst one in the batch due to an improperly prepared pan. Can be used to refer to a terrible 'first' of anything.
The recipe says it makes eight pancakes, but it's really only seven because no one's going to eat the sacrificial pancake.
She winced, thinking about her earliest dating fiasco, but comforted herself by deciding that her failure of a first boyfriend was merely the sacrificial pancake in her dating career.