Possible Definitions:
1. seal () A compound hydraulic valve for regulating the passage of the gas through a set of purifiers so as to cut out each one in turn for the renewal of the lime.
2. Seal (n.) Any aquatic carnivorous mammal of the families Phocidae and Otariidae.
3. Seal (n.) 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.
4. Seal (n.) 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.
5. Seal (n.) That which seals or fastens; esp., the wax or wafer placed on a letter or other closed paper, etc., to fasten it.
6. Seal (n.) That which confirms, ratifies, or makes stable; that which authenticates; that which secures; assurance.
7. Seal (n.) 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.
8. Seal (v. t.) To set or affix a seal to; hence, to authenticate; to confirm; to ratify; to establish; as, to seal a deed.
9. Seal (v. t.) 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.
10. Seal (v. t.) To fasten with a seal; to attach together with a wafer, wax, or other substance causing adhesion; as, to seal a letter.
11. Seal (v. t.) Hence, to shut close; to keep close; to make fast; to keep secure or secret.
12. Seal (v. t.) To fix, as a piece of iron in a wall, with cement, plaster, or the like.
13. Seal (v. t.) To close by means of a seal; as, to seal a drainpipe with water. See 2d Seal, 5.
14. Seal (v. t.) Among the Mormons, to confirm or set apart as a second or additional wife.
15. Seal (v. i.) To affix one's seal, or a seal.
