Definition
The word 'testaceous' describes something that relates to or resembles shells, especially those of mollusks. Think of it as having a shell-like quality or being made of shells. A 'testaceous' material is often hard, brittle, and layered. Snails, clams, and oysters are examples of 'testaceous' creatures. It can also refer to the reddish-brown color of some shells. This adjective emphasizes the protective outer layer.