écaille

Écaille is a French feminine noun meaning a small plate or scale. The term is used across domains to describe something that has the shape, texture, or arrangement of overlapping plates.

In biology, écaille most often refers to the scales that cover the skin of fish and reptiles. These protective plates vary in size, shape, and arrangement between species and contribute to characteristics such as camouflage, protection, and locomotion.

In decorative arts and material culture, écaille also denotes tortoiseshell, the hard outer shell of certain sea turtles. The expression écailles de tortue is used for tortoiseshell itself, historically prized for inlays, jewelry, combs, and even musical instruments. Because many tortoise species are protected, the trade and use of tortoiseshell are now subject to strict legal restrictions in many countries.

The sense of écaille extends to patterns and textures as well. In architecture, ceramics, textiles, and heraldry, an écaillé or scale-like pattern describes surfaces composed of overlapping, curved elements that resemble fish or reptile scales. This motif appears in tiling, mosaics, and decorative surfaces to evoke a natural, orderly gradation.

Etymologically, the core idea ties to the idea of small, flat pieces forming a continuous layer. In contemporary usage, écaille can thus refer to the natural scales of animals, to tortoiseshell material, or to a visual pattern that imitates scales, depending on the context.