Term used for an area where a piece of the porcelain paste or even just the glaze, is missing after having been "chipped" off.
Glaze blisters are different from chips, and can occur in large areas without being considered a damage, in particular on pieces from periods where blisters are to be expected, such as the end of the Ming dynasty.
On utilitarian export porcelain, some chips are common at the footrim, and do not detract from the value. They might even be caused by the firing method and are considered normal.
On Chinese market wares and in particular Imperial wares, any imperfections, also chips of the foot rim are not expected and will detract from the value.