sealer

from The Century Dictionary.

• noun One who seals; one who stamps with a seal.
• noun In the United States, an officer appointed to examine and test weights and measures, and set a stamp upon such as are true to the standard; also, an officer who inspects and stamps leather; also, one who inspects brick-molds, sealing such as are of proper size.
• noun A man or a ship engaged in the seal-fishery.

from the GNU version of the Collaborative International Dictionary of English.

• noun A mariner or a vessel engaged in the business of capturing seals.
• noun One who seals; especially, an officer whose duty it is to seal writs or instruments, to stamp weights and measures, or the like.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tool used to seal something.
• noun A person who is employed to seal things.
• noun A coating designed to prevent excessive absorption of finish coats into pourous surfaces; a coating designed to prevent bleeding.
• noun A person who hunts seals.
• noun A vessel engaged in the business of capturing seals.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an official who affixes a seal to a document
• noun a kind of sealing material that is used to form a hard coating on a porous surface (as a coat of paint or varnish used to size a surface)