Fibres are long, thin, and strong. Plants and animals have evolved special fibres to perform specific jobs; you don’t see trees made from wool or sheep made from wood! A single fibre by itself is not much good but when they are brought together, they can create different properties.
In textiles we have natural and man-made fibres. These come in short staple form or continuous filaments. Fibres are a textile designer’s basic building block.