What is the meaning of sealing?

noun

• The act of treating something to make it repel water.
  • synonyms: waterproofing

verb

• Make tight; secure against leakage.
  • usage: "seal the windows"
  • synonyms: seal, seal off
• Close with or as if with a seal.
  • usage: "She sealed the letter with hot wax"
  • synonyms: seal
• Decide irrevocably.
  • usage: "sealing dooms"
  • synonyms: seal
• Affix a seal to.
  • usage: "seal the letter"
  • synonyms: seal
• Cover with varnish.
  • synonyms: varnish, seal
• Hunt seals.
  • synonyms: seal