What is the meaning of demonstrate?

verb

• Give an exhibition of to an interested audience.
  • usage: "She shows her dogs frequently"; "We will demo the new software in Washington"
  • synonyms: show, demo, exhibit, present
• Establish the validity of something, as by an example, explanation or experiment.
  • usage: "The experiment demonstrated the instability of the compound"; "The mathematician showed the validity of the conjecture"
  • synonyms: prove, establish, show, shew
• Provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes.
  • usage: "His high fever attested to his illness"; "The buildings in Rome manifest a high level of architectural sophistication"; "This decision demonstrates his sense of fairness"
  • synonyms: attest, certify, manifest, evidence
• March in protest; take part in a demonstration.
  • usage: "Thousands demonstrated against globalization during the meeting of the most powerful economic nations in Seattle"
  • synonyms: march