A person who carries, makes, designs, or bears a banner; someone associated with or responsible for banners.
From 'banner' + '-er' (agent noun suffix). The '-er' suffix creates nouns for people who perform or are associated with an action or object, just as 'baker' is one who bakes.
Bannerers were specialized craftspeople in medieval times—they weren't just flag carriers but artists and engineers who created heraldic designs that had to be visible, memorable, and legally distinctive according to complex heraldic rules.
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