triangular headscarf; triangle headband; triangular bandana
A triangular piece of cloth worn on the head, often tied under the chin. Commonly associated with traditional workwear, homemakers, or historical settings.
My grandmother always wore a triangular headscarf when cleaning.
In period dramas, town girls often wear triangular headscarves.
Compound of 三角 (さんかく, 'triangle') and 頭巾 (ずきん, 'hood, headscarf'). The exact historical origin is uncertain, but the term describes the shape and function of the cloth.