There are a variety of synonyms for the term 'potter earths'. These include: 1. Ball clays - These are a type of sedimentary clay that is commonly used in pottery. 2. Kaolin - This is a type of clay that is used in ceramics, medicine, paper, and many other industries. 3. Fireclays - These are a type of clay that is able to withstand high temperatures and are used in the production of ceramics, bricks, and refractory materials. 4. Bentonite - This is a type of clay that is used in a variety of industries, including agriculture, foundry, and cosmetics. 5. Fuller's earth - This is a type of clay that is used in the textile industry to remove impurities from fabric. Overall, these synonyms all refer to different types of clay that are used in a variety of industrial and commercial applications.