A tile adhesive is a bonding agent used to secure tiles onto surfaces like walls or floors. It's typically a paste-like substance that provides strong adhesion, ensuring tiles remain in place over time. Most adhesives are designed to work with specific types of tiles and substrates, so it's essential to choose the right one for your project. They come in various formulations, including cement-based, epoxy, and acrylic, each with its own set of properties and application methods.