Tapeta

Part of speech: noun

Definitions

1. A layer of tissue in the eye, particularly in the choroid, that reflects light and aids in vision in low-light conditions
2. The reflective layer in some animal eyes that enhances night vision by improving light sensitivity
3. A structure found behind the retina in various animals, functioning to increase visual acuity in dim environments

Etymology: "Tapeta" is the plural of "tapetum", the layer of cells behind the retina that reflects light back through the eye, which is why animals' eyes sometimes glow at night. The Latin word "tapētum" meant a carpet or tapestry, a covering spread over a surface. Its ultimate source is the Ancient Greek "tápēs", meaning a carpet or rug, so the anatomical term was named for a textile. The link to eyes comes from the look of the layer rather than from any link to fabric. Anatomists borrowed the old word for a woven covering because the reflective tissue spreads across the back of the eye like a rug laid over a floor. The word "tapet", a doublet of this same Latin source, reached English earlier with the sense of a tapestry hanging, so English speakers have long had both forms available.