In heraldry, a very narrow vertical stripe or border, often used as a thin line dividing heraldic fields.
From Old French burelle, a diminutive form of bure, the coarse fabric. The narrow heraldic line was named for its resemblance to a thin thread in weaving.
A burelle is basically the narrowest possible line in heraldry—if you can barely see it, that's intentional, because it's meant to be an elegant, subtle division between colors on a shield.
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