In heraldry and architecture,[1] a line which is drawn nebuly is made up of a series of bulbous protrusions, which are supposed to resemble clouds (Latin nebula: a mist, vapor, or cloud).(OED)
The title of the 1903 book The Nebuly Coat refers to the coat of arms of one of the characters.[2]
Its use in coats of arms can be seen in the cases of Jones and Munk, both Canada, FLEETWOOD BOROUGH COUNCIL, England and HYDE BOROUGH COUNCIL, England