Nulllinien

Nulllinien, a term in German-language technical literature, denotes a line representing zero value in diagrams, charts, and various physical contexts. The precise meaning depends on the domain, but in general the Nulllinie represents a baseline or locus where the measured quantity equals zero.

In mathematics, the Nulllinie of a real-valued function f is the set of points where f(x) = 0. On a plot, this corresponds to the intersection of the graph with the horizontal axis.

In data visualization and statistics, the term commonly refers to the horizontal line at zero, used as a baseline for residuals, errors, or signal measurements. It helps interpret deviations from the zero reference.

In physics and engineering, a Nulllinie can denote a reference line where a potential, field, or current is zero, and is used in diagrams that show distributions or waveforms. In signal processing, the term may be used informally to describe zero-crossings of a waveform, which are points where the signal changes sign.

Origins and usage: The term derives from the German words Null and Linie. It is primarily used in German-language texts and in European technical education. English-language sources more often translate the concept as "zero line" or "zero-crossing line" depending on context.

See also: Zero line; baseline; zero-crossing; axis; reference line.