Stratum 1 refers to the first layer of a hierarchical structure, often used in various fields such as geology, sociology, and computer science. In geology, it represents the topmost layer of rock or soil, while in sociology, it can denote the highest social class within a stratified society. In the context of computer networks, stratum 1 is associated with timekeeping systems, specifically referring to servers that are directly connected to an accurate time source, such as an atomic clock or GPS. These servers provide precise time to lower stratum servers, ensuring synchronization across networks.