The name of a family of materials, such as the polycarbonate family.
Each material is a member of a family of materials. The shortened version of a family name is the family abbreviation. For example, PC is the family abbreviation for polycarbonate.
Some families contain subsets, and there is an abbreviation for each subset. For example, TPE, TPO, TPU, and TPR are family abbreviations within the thermoplastic elastomer family.