1. (n.) Any aquatic carnivorous mammal of the families Phocidae and Otariidae.

2. (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.

3. (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.

4. (n.) That which seals or fastens; esp., the wax or wafer placed on a letter or other closed paper, etc., to fasten it.

5. (n.) That which confirms, ratifies, or makes stable; that which authenticates; that which secures; assurance.

6. (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 drain trap.

7. (v. t.) To set or affix a seal to; hence, to authenticate; to confirm; to ratify; to establish; as, to seal a deed.

8. (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.

9. (v. t.) To fasten with a seal; to attach together with a wafer, wax, or other substance causing adhesion; as, to seal a letter.

10. (v. t.) Hence, to shut close; to keep close; to make fast; to keep secure or secret.

11. (v. t.) To fix, as a piece of iron in a wall, with cement, plaster, or the like.

12. (v. t.) To close by means of a seal; as, to seal a drainpipe with water. See 2d Seal, 5.

13. (v. t.) Among the Mormons, to confirm or set apart as a second or additional wife.

14. (v. i.) To affix one's seal, or a seal.

John Hancock OK X accept acceptance accredit affirm affirmance affirmation agree on terms amen approbation approval approve aroma assurance assure attest attestation attribute authenticate authentication authorization authorize autograph badge bang banner bar barricade batten batten down bearing beige billhead blaze blaze a trail blemish blotch bolt book stamp bookplate boss brand broad arrow brown brownish brownish-yellow brunet bump burin button button up cachet cap of dignity cap of maintenance cartouche cast casting certification certify chalk chalk up character characteristic check check off chocolate choke choke off christcross cicatrize cinnamon cipher clap clinch close close off close up coat of arms cocoa cocoa-brown coffee coffee-brown colophon concavity conclude configuration confirm confirmation constrict contain contract convexity cork coronet corroborate corroboration cosign counterfoil countermark countersign countersignature counterstamp cover crest cross crown cut dactylogram dactylograph dapple dash decide define delimit demarcate dent design determine device diadem die differentia differential dint discolor distinctive feature docket dot drab dun dun-brown dun-drab earmark ecru emblem embossment endorse endorsement engrave engraving tool ensure ermine escutcheon etching ball etching ground etching needle etching point evidence excrescence fasten fawn fawn-colored feature figure fingerprint fix flavor fleck fold fold up footmark footprint footstep form formalize fossil footprint freckle fuscous gash give permission give the go-ahead give the imprimatur give thumbs up go-ahead government mark government stamp graver great seal green light grege guarantee guaranty gust hallmark hand hatch hazel ichnite ichnolite identification idiocrasy idiosyncrasy image impress impression imprimatur imprint indent indentation indention index indicant indicator individualism initial initials insignia intaglio key keynote khaki label last latch letterhead line lineaments lock lock out lock up logo logotype lump lurid make a mark mannerism mark mark of signature mark off mark out marking masthead matrix measure mint mold molding monogram mottle nature needle negative nick nod notarization notarize notch note notice notification nut-brown occlude