ban ‧ ner /ˈbænə $ -ər/ BrE AmE noun [countable]
[ Date: 1200-1300 ; Language: Old French ; Origin: banere ]
1 . a long piece of cloth on which something is written, often carried between two poles:
The onlookers were shouting, cheering, and waving banners.
2 . a belief or principle
carry/raise/wave etc the banner of something (=publicly support a particular belief etc)
She’d never felt the need to carry the banner of feminism.
under the banner of something
They marched under the banner of equal educational opportunity.
3 . under the banner of something as part of a particular group or organization:
The oil-producing countries joined together under the banner of OPEC.
4 . a flag