What is the meaning of extraneous?

adjective

• Not pertinent to the matter under consideration.
  • usage: "an issue extraneous to the debate"; "the price was immaterial"; "mentioned several impertinent facts before finally coming to the point"
  • synonyms: immaterial, impertinent, orthogonal
• Not essential.
  • usage: "the ballet struck me as extraneous and somewhat out of keeping with the rest of the play"
• Not belonging to that in which it is contained; introduced from an outside source.
  • usage: "water free of extraneous matter"; "foreign particles in milk"
  • synonyms: foreign
• Coming from the outside.
  • usage: "extraneous light in the camera spoiled the photograph"; "relying upon an extraneous income"; "disdaining outside pressure groups"
  • synonyms: external, outside