The term 'of a subset' can be described as a sectoral, which is an 8 letter word. A sectoral is a subset of a larger group or population that has been divided into smaller parts. It is often used to refer to a specific area of a business or industry, such as the automotive sector or the banking sector. It can also refer to a geographic region, such as the European Union or the Middle East. In general, sectorals are used to divide a large group into smaller, more manageable parts.