A container which held heat; sometimes it was shaped as a ball to warm the hands of a priest before the *eucharist, when it was known as a 'pome' (Fr. pomme = apple). Later, in the 16c, it was the heated room in a monastery. [< Lat. calefacto = to make warm]
Cf. Misericord3
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.