Merriam-Webster Collegiate Dictionary - seal

 I. noun  (plural ~s; also ~)  Etymology: Middle English sele, from Old English seolh; akin to Old High German selah ~  Date: before 12th century  1. any of numerous carnivorous marine mammals (families Phocidae and Otariidae) that live chiefly in cold regions and have limbs modified into webbed flippers adapted primarily to swimming; especially a fur ~ or hair ~ as opposed to a sea lion  2.  a. the pelt of a fur ~  b. leather made from the skin of a ~  3. a dark brown  II. intransitive verb  Date: 1828 to hunt ~s  III. noun  Etymology: Middle English sele, seel, from Anglo-French ~, sel, from Latin sigillum ~, from diminutive of signum sign, ~ — more at sign  Date: 13th century  1.  a. something that confirms, ratifies, or makes secure ; guarantee, assurance  b.  (1) a device with a cut or raised emblem, symbol, or word used especially to certify a signature or authenticate a document  (2) a medallion or ring face bearing such a device incised so that it can be impressed on wax or moist clay; also a piece of wax or a wafer bearing such an impression  c. an impression, device, or mark given the effect of a common-law ~ by statute law or by American local custom recognized by judicial decision  d. a usually ornamental adhesive stamp that may be used to close a letter or package; especially one given in a fund-raising campaign  2.  a. something that secures (as a wax ~ on a document)  b. a closure that must be broken to be opened and that thus reveals tampering  c.  (1) a tight and perfect closure (as against the passage of gas or water)  (2) a device to prevent the passage or return of gas or air into a pipe or container  3. a ~ that is a symbol or mark of office  IV. transitive verb  Date: 14th century  1.  a. to confirm or make secure by or as if by a ~ ~ the deal  b. to solemnize for eternity (as a marriage) by a Mormon rite  2.  a. to set or affix an authenticating ~ to; also authenticate, ratify  b. to mark with a stamp or ~ usually as an evidence of standard exactness, legal size, weight, or capacity, or merchantable quality  3.  a. to fasten with or as if with a ~ to prevent tampering  b. to close or make secure against access, leakage, or passage by a fastening or coating  c. to fix in position or close breaks in with a filling (as of plaster)  4. to determine irrevocably or indisputably that answer ~ed our fate SEAL  abbreviation sea, air, land (team) SEA-LANE  noun  Date: 1869 an established sea route