Word of the day: to beal; to suppurate, to gather, to weep pus. Obsolete in standard English. The OED describes that it is still in use in Scotland, and I can report today that it is used in the area of the East Donegal plantation.
It is either a Norse doublet of boil (in the meaning of a furuncle) or an internal English variant on the word. Cf. German die Beule with the same meaning.