Synonyms for Seal:

n.

carriage, chamber, bucket, ancillary, bearing, ball bearing, cam, camshaft. lock out, block off, bar, jam something open/shut, close off, close up. credit slip, ecolabel, bar code, coupon, food stamp, courtesy card, docket, discount card, gift certificate, food coupon. overflow, flip top, lid, bung, compartment, cap, lip, mouth. humpback whale, man-of-war, conger eel, coral, dolphin, humpback, cuttlefish, jellyfish, plankton, octopus. approval (noun)
permit, allowance, authorization, permission.
artifact (noun)
sealing wax, stamp.
authentication; stamp (noun)
authorization, insignia, tie, tape, permit, signet, cachet, allowance, permission.
badge (noun)
emblem, ring, scepter, talisman, regalia, tartan, staff, crown, baton, tiara, ermine, signet, uniform, wand, coronet, orb, badge, pall, mantle, insignia, mortarboard.
closure (noun)
choke, plug, cork, obstruction, stopper.
cover (noun)
varnish.
fastener (noun)
buckle, latch, bond, rabbet, snap, thread, knot, Vinculum, bracket, band, fuse, braid, suture, bonding, bolt, medium, glue, pin, cleat, knitting, ligament, splice, skewer, guy, chain, hook, weld, nail, tie, cinch, zipper, button, hawser, cotter, grapnel, spike, stitch, string, binding, twine, clasp, closure, cincture, lock, fastening, link, belt, paste, rivet, clip, strap, catch, vise, hasp, hitch, middleman, coupling, cement, stay, go-between, lace, mediator, tack, fastener, hinge, staple, brad, agent, clamp, clinch, anchor, binder, connector, brace, mucilage.
seal (noun)
stamp, seal of approval, cachet, varnish, sealing wax, sealskin.

v.

close (verb)
block, fasten, stop, shut, join, secure, close, barricade, jam.
ensure, finalize (verb)
clinch, stamp.
make airtight (verb)
cork, paste, stopper, stop, secure, shut, fasten, close, plug.

Other synonyms:

close off. block off, lock out. bung, close up. cap. bar. approve
permit.
close
shut.
occlude
lock out.
plug
bung.
stop up
plug.
Other relevant words:
stamp, bearing, lock out, authorization, seal of approval, varnish, close off, sealing wax, cap, cachet, allowance, close up, permit, bung, tape, docket, bar, permission, sealskin.

Usage examples for seal

  1. One or another of those who are out after seal will be sure to find it. – Eskimo Folktales by Unknown
  2. It would have set the seal on an evening of glorious success, completed it, as it were. – The Splendid Folly by Margaret Pedler
  3. He opened the letter, and, as he broke the seal his face was like morning. – Bye-Ways by Robert Smythe Hichens