BILL OF HEALTH
A certificate, properly authenticated, that a certain ship or vessel therein named, comes from a place where no contagious distempers prevail, and that none of the crew at the time of her departure were infected with any such distemper.
It is generally found on board of ships coming from the Levant, or from the coast of Barbary, where the plague so frequently prevails. The bill of health is necessary whenever a ship sails from a suspected port or when it is required at the port of destination.
In Scotland the name of bill of health has been given to an application made by an imprisoned debtor for relief under the Act of Sederunt. When the want of health of the prisoner requires it, the prisoner is indulged, under proper regulations, with such a degree of liberty as may be necessary to restore him.
In modern days it is part of a generic term meant to indicate all is OK with something. i.e. 'A clean bill of health.'