Fiber (American English) or Fibre (International English) are hair-like materials (they look like threads) that form the building blocks from which yarn and fabric are made.

In order to determine a fabric's appearance, how it would wear and its care, it is important to understand the characteristics of the fibers from which the fabric is made.

The Character or personality of any textile structure, end-use product,
i.e., its appearance, texture, handles, wear performance, mechanical
Properties, etc., is generally influenced by four factors:

1. The fiber or blend of fibers used

2. Yarn structure or structures - size, twist, etc.

3. Fabric structure - weave, knit, nonwoven