ndot

Ndot is a notation used in mathematics and physics to indicate the time derivative of a quantity denoted by N. The symbol consists of a dot placed over the letter N, yielding Ṅ, and this convention is part of the broader family of dot notations that signify differentiation with respect to time.

In dynamical systems and related fields, Ṅ commonly represents the rate of change of N with respect to time, expressed as dN/dt. This notation applies to scalar quantities as well as vector quantities, in which case Ṅ denotes the vector of time derivatives of the components of N. It appears in a wide range of contexts, including population dynamics, chemical kinetics, physics, and control theory, where equations describe how N evolves over time.

The use of the dot notation traces back to Newton’s notation for time derivatives and has become a compact, widely adopted shorthand in mathematical modeling and engineering. It offers a concise way to write differential equations and to communicate dynamic behavior without repeatedly writing dN/dt.

Outside of mathematics and the sciences, the term Ndot can also appear as a proper noun or branding in unrelated domains. It is important to distinguish such uses from the mathematical Ṅ notation, and to note that Ndot is not interchangeable with similarly spelled acronyms or entities such as NDOT, which refers to different organizations in other contexts.

See also: dot notation, time derivative, Newton’s notation, Ṅ in physics.