Meaning : Establish the validity of something, as by an example, explanation or experiment.
Example :
The experiment demonstrated the instability of the compound.
The mathematician showed the validity of the conjecture.
Meaning : Provide evidence for. Stand as proof of. Show by one's behavior, attitude, or external attributes.
Example :
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.
Meaning : March in protest. Take part in a demonstration.
Example :
Thousands demonstrated against globalization during the meeting of the most powerful economic nations in Seattle.
Synonyms : march