banners
A banner is a long strip of cloth with something written on it. Banners are usually attached to two poles and carried during a protest or rally.
A large crowd of students followed the coffin, carrying banners and shouting slogans denouncing the government.
一大群学生跟在灵柩的后面,举着横幅,高喊口号谴责政府。
under the banner of
If someone does something under the banner of a particular cause, idea or belief, they do it saying that they support that cause, idea or belief.
Russia was the first country to forge a new economic system under the banner of Marxism.
苏联是第一个在马克思主义的旗帜下建立新的经济体制的国家。