march in protest; take part in a demonstration; "Thousands demonstrated against globalization during the meeting of the most powerful economic nations in Seattle"
a belief that can guide behavior; "the architect has a theory that more is less"; "they killed him on the theory that dead men tell no tales"
a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
upright in position or posture; "an erect stature"; "erect flower stalks"; "for a dog, an erect tail indicates aggression"; "a column still vertical amid the ruins"; "he sat bolt upright"