What is the term for any fiber created artificially, like nylon or polyester?

The correct term for fibers created artificially, such as nylon or polyester, is synthetic fiber. Synthetic fibers are those that are manufactured from chemical processes, often derived from petroleum-based products. These fibers are designed to possess specific qualities, such as durability, elasticity, and resistance to moisture, which are often not found in natural fibers.

While "man-made fiber" can sometimes refer to synthetic fibers, it is a broader term that can also include regenerated fibers like rayon. Thus, it doesn't specifically and exclusively categorize fibers made entirely through chemical processes. Synthetic fiber, however, specifically identifies those fibers engineered from synthetic materials, making it the most accurate choice for the question regarding artificially created fibers.

The other terms do not fit this definition as closely as synthetic fiber does. Natural fiber refers to fibers obtained from plants or animals, while processed fiber may imply some form of treatment instead of focusing on the fiber's origin as synthetic.