What aspect of writing is described as providing supporting details for a main idea?

The term that describes providing supporting details for a main idea is development. In writing, development refers to the process of expanding upon the main idea by offering specific examples, evidence, or elaboration that enhances understanding and supports the central thesis. This is crucial in creating a compelling and coherent argument or narrative, as it helps the reader grasp the significance and relevance of the main idea effectively.

The other terms, while related to writing, do not match this particular definition. Explanation typically involves clarifying concepts or ideas but does not necessarily focus on providing supportive details. Illustration usually refers to using examples or visuals to clarify an idea but may not encompass the broader scope of detailing or expanding a main concept. Analysis involves breaking down a text or idea into its components to understand or interpret it, which is a different function than simply supporting a main idea with details.