A group of closely related chemicals whose physico-chemical, ecotoxicological or toxicological properties are similar or follow a regular pattern as a result of structural similarity
The Association of Petrochemicals Producers in Europe (APPE), The European petrochemical industry, Glossary of Terms on Chemical Safety for Use in IPCS Publications, van Nieuwenhuyse, Brussels 2006. http://www.petrochemistry.eu/glossary.html, (Petrochem Ind - Brit) {473}