What is the meaning of concatenation?

noun

• The state of being linked together as in a chain; union in a linked series.
• The linking together of a consecutive series of symbols or events or ideas etc.
  • usage: "it was caused by an improbable concatenation of circumstances"
• A series of things depending on each other as if linked together.
  • usage: "the chain of command"; "a complicated concatenation of circumstances"
  • synonyms: chain
• The act of linking together as in a series or chain. .