n.

1. fastener consisting of a resinous composition that is plastic when warm; used for sealing documents and parcels and letters;
   sealing wax
2. a device incised to make an impression; used to secure a closing or to authenticate documents;
   stamp
3. the pelt or fur (especially the underfur) of a seal;
   sealskin
   
   • a coat of seal
4. a member of a Naval Special Warfare unit who is trained for unconventional warfare;
   Navy SEAL, SEAL
   
   • SEAL is an acronym for Sea Air and Land
5. a stamp affixed to a document (as to attest to its authenticity or to seal it)
   
   • the warrant bore the sheriff's seal
6. an indication of approved or superior status;
   cachet, seal of approval
7. a finishing coat applied to exclude moisture
8. fastener that provides a tight and perfect closure
9. any of numerous marine mammals that come on shore to breed; chiefly of cold regions

v.

1. close with or as if with a seal
   
   • She sealed the letter with hot wax
2. make tight; secure against leakage;
   seal off
   
   • seal the windows
3. decide irrevocably
   
   • sealing dooms
4. affix a seal to
   
   • seal the letter
5. cover with varnish;
   varnish
6. hunt seals