What does «flanquera» mean in Spanish?

Piece of the armor of war horses that covered the flanks and part of the flanks of the animal. It was secured with straps to the petral and the grupera. The armor (or barda) of the cavalry called "heavy" during the reign of Charles V was completed with the testera (or frontal) for the head, the capizana for the mane, the petral or breastplate for the front area and the grupera for the rump.

Examples of use in Spanish: "Parecía no importarle la guata ni la flanquera de malla que le protegían los flancos, pero no podía soportar la testera, así que sacudía la cabeza e intentaba morder el cuero", Lancelot, Giles Kristian - 2020