Bottled water with added vitamins, minerals, etc., sold as a health drink.

(mathematics) In harmonic analysis, any of a complete orthogonal set of functions that can be used to represent any discrete function.

(combinatorics) A Boolean function f: Z ₂ⁿ→ Z ₂ whose Walsh transform has constant absolute value.

(combinatorics) A function from the natural numbers to the set {−1, 0, 1} which maps perfect squares to 0, prime numbers to −1, and is multiplicative.

(mathematics) A function in a system of differential equations that is only a function of time, unaffected by the other variables; or, more generally, any non-homogeneous source function in any variable.

(mathematics) A function obtained from a continuous function by transfinite iteration of the operation of forming pointwise limits of sequences of functions.

plural of functional constituency

(computer science) A function that defines the output of a particular node in an artificial neural network on the basis of its inputs.

(Hong Kong, Macau, politics) A type of non-geographical electoral constituency in which the constituents are defined by their professional occupation.

(computing) A requirement of a piece of software, such as accessibility or portability, that is not a specific, measurable aspect of performing a particular task.