Copious means abundant or plentiful, existing in large amounts. When a scientist takes copious notes during an experiment, she writes down lots of detailed observations. When it rains copiously, water pours down in great quantities.

The word suggests an amount so large that it's remarkable or noticeable. A student who does copious research for a project gathers information from many sources and accumulates pages of material. A baker might add copious amounts of chocolate chips to cookies, far more than the recipe calls for.

You'll often see copious paired with words like notes, amounts, quantities, or details. If your teacher assigns a research paper and says “use copious evidence,” she wants you to include plenty of supporting facts and examples, not just one or two. When a witness provides copious details about what she saw, she remembers and shares an abundance of specific information that helps others understand what happened.