levels

Levels are distinct stages or layers within a system that is organized hierarchically or spatially. The term can refer to floors in a building, horizontal planes within a space, or stages in a process, competition, or game. A level is typically bounded by clear boundaries that separate it from adjacent levels.

In architecture and construction, a level usually means a floor or story of a building, such as the ground level or a mezzanine. Levels are used in design and safety planning and are often labeled by numbers or names, affecting navigation and evacuation routes.

In video games and other media, levels are discrete stages that players complete to advance. Levels commonly introduce new objectives, mechanics, or enemies and are graded by difficulty. Level design focuses on pacing, challenge, and reward structures; progress may be saved at checkpoints or after a level is finished.

In mathematics and science, level has several precise uses. A level set or level curve comprises all inputs that yield a given value under a function. In geography and physics, level can refer to contour lines, sea level, or potential surfaces. In environmental monitoring, levels describe quantities that vary over time or space, such as water level or gas concentration.

In measurement and safety contexts, a level indicates a quantity read by a gauge or sensor, such as liquid level, noise level, or alert level. Levels provide thresholds for alarms, controls, and decision-making processes.