A "layer" refers to a distinct level or stratum within a structure or system. In various contexts, such as geology, a layer can represent different types of rock or soil, while in technology, it may refer to a level of abstraction in software architecture, like the presentation layer or data layer. Each layer serves a specific purpose and interacts with other layers to create a cohesive whole. In everyday life, layers can be seen in clothing, where different garments are worn on top of one another for warmth or style. Similarly, in cooking, a layered cake consists of multiple tiers of cake and frosting, each contributing to the overall flavor and texture. Layers help organize and enhance complexity in both natural and human-made systems.