What does Other Fibres (also Altre Fibre) mean?
A measure of the additional fibres included in a garment that only make up a small percentage of the overall fabric content.
Heddels explains Other Fibres (also Altre Fibre)
Almost all garments have tags that identify the fiber content. Because many fabrics are blended with a mix of various natural and synthetic fibers, it may not be practical to list all of the fibers included, especially if some make up only a small percentage of the finished fabric’s content. Thus, manufacturers may use the term Other Fibers to acknowledge the other fiber types included in the fabric. Altre Fibre is the Italian translation of other fibers. This phrase is commonly found on content tags and reflects the high percentage of fabric produced in Italy. Manufacturers will often use the abbreviation A.F. on their labels to mean other fibers.
Here is an example of other fibres that can be included in garments: