ratiodefined

Ratiodefined is a neologism used to describe a quantity or construct that is defined by a ratio of two underlying quantities. It is not a standard term in formal mathematics, but it can serve as a concise descriptive label in discussions of ratio-based definitions.

Definition: In its simplest form, a ratiodefined quantity Q is given by Q = A/B, where A and B are real-valued quantities and B ≠ 0. More generally, Q may be defined as a rational function of several components, but the defining feature remains the dependence on a quotient.

Examples: The aspect ratio of an image, defined as width/height, is a classic ratiodefined quantity. In physics, velocity is a ratio of distance to time. In statistics, a rate such as events per unit exposure is also a ratio.

Properties and considerations: Denominators must be nonzero. The value can be dimensionless if the numerator and denominator share the same units; otherwise, it carries units. Scaling both numerator and denominator by the same factor leaves Q unchanged.

See also: ratio, proportion, rate, normalization, dimensionless quantity.