What is "in pectore"

In pectore ( Latin for "in the breast/heart"; pronounced ) is a term used in the Catholic Church to refer to appointments to the College of Cardinals by the Pope whose names are not publicly revealed (hence reserved by the Pope "in his bosom"). This right of the pope is rarely exercised, usually in circumstances where the pope wants to make a statement for later historians about the honour due a particular cleric, while not wanting to endanger that same cleric in his present circumstances of persecution.