Undercoats are an essential part of the painting process. These base layers are applied before the topcoat to boost adhesion, provide a consistent texture, and improve the overall durability of the finish. There are many names used for an undercoat, and some of the synonyms include basecoat, primer, sealer, ground coat, foundation, and underpaint. These terms are frequently used interchangeably by professionals and DIY enthusiasts, but they often refer to the same thing. No matter what the undercoat is called, it is always crucial to ensure that proper preparation and application of it are done to achieve the desired results.