1) a large sea-animal with short fur and wide flippers; a piece of wax, lead etc stamped with a design, attached to a document to show that it is genuine, or to a letter, packet, box, bottle, door etc to show that it has not been opened; something used to make an opening airtight or watertight (seal)
completely airtight
airtight
(of materials) not allowing water etc to pass through; (of a person) not moved or influenced (by something)
unable to be penetrated
