any aquatic carnivorous mammal of the families phocidae and otariidae.-an engraved or inscribed stamp, used for marking an impression in wax or other soft substance, to be attached to a document, or otherwise used by way of authentication or security.-wax, wafer, or other tenacious substance, set to an instrument, and impressed or stamped with a seal; as, to give a deed under hand and seal.-that which seals or fastens; esp., the wax or wafer placed on a letter or other closed paper, etc., to fasten it.-that which confirms, ratifies, or makes stable; that which authenticates; that which secures; assurance.-an arrangement for preventing the entrance or return of gas or air into a pipe, by which the open end of the pipe dips beneath the surface of water or other liquid, or a deep bend or sag in the pipe is filled with the liquid; a draintrap.-to set or affix a seal to; hence, to authenticate; to confirm; to ratify; to establish; as, to seal a deed.-to mark with a stamp, as an evidence of standard exactness, legal size, or merchantable quality; as, to seal weights and measures; to seal silverware.-to fasten with a seal; to attach together with a wafer, wax, or other substance causing adhesion; as, to seal a letter.-hence, to shut close; to keep close; to make fast; to keep secure or secret.-to fix, as a piece of iron in a wall, with cement, plaster, or the like.-to close by means of a seal; as, to seal a drainpipe with water. see 2d seal, 5.-among the mormons, to confirm or set apart as a second or additional wife.-to affix one's seal, or a seal.