An adjective describing things through which light passes or which are clearly visible. Physical applications include transparent or translucent materials like glass through which one can see. It can describe something heated until red-hot and glowing. Metaphorically, it extends to things that are manifest, clear, or distinct—not hidden or obscure. Medical texts use it for veins that are distinctly visible. Another sense identifies things that are conspicuous or prominent among others. The unifying thread is visibility: either light passing through something, or something being clearly apparent.