What is the meaning of deletion?

noun

• Any process whereby sounds or words are left out of spoken words or phrases.
  • synonyms: omission
• Genetics) the loss or absence of one or more nucleotides from a chromosome. (
• The omission that is made when an editorial change shortens a written passage.
  • usage: "an editor's deletions frequently upset young authors"; "both parties agreed on the excision of the proposed clause"
  • synonyms: excision, cut
• The act of deleting something written or printed. .