The term "base coat" is commonly used in the world of painting, where it refers to the initial layer applied to a surface before adding subsequent coats of paint. However, there are several other potential synonyms or related terms that could also apply depending on the context. For example, some other words that might be used include primer, undercoat, sealant, or even foundation. Each of these words refers to a substance or coating that is applied first or laid down as a base layer to prepare the surface for further work. Whether you are a painter or simply looking to expand your vocabulary, these synonyms for base coat can help you communicate more effectively.