A watermark is a visible mark associated with water contact, often left after moisture changes or dries. The appearance can reflect residue or a change in the finish.
What this means at your property
A ring on a ceiling may remain after a repaired leak, while a new leak can occur with little immediate discoloration. A mark alone does not establish whether the material is currently wet or when the event occurred.
What should be checked before painting over it?
Document the mark and investigate any unresolved source. Ask for assessment of the underlying material and moisture condition before preparation and repainting, so a cosmetic repair does not hide an active problem.