The ratio of the Laplace transform of the primary feedback signal of a control system to that of the actuating signal

(mathematics) The logarithm of a trigonometric function

(computing) Any of a set of subroutines supplied with a language or system that can be called to perform standard mathematical functions efficiently

(physics) A relationship that describes the probability of a particle that collides with another being scattered in any particular manner

(mathematics) A function that gives the relative probability that a discrete random variable is exactly equal to some value.

(mathematics, physics) A function which specifies the average density of atoms, molecules etc in three dimensions from a given point.

(computing) A function key whose function can be assigned by the user or by a program.

(physics) A function which is a solution of Schrödinger's wave equation; the psi function

(computing) A program or subroutine, provided by the user rather than being built into the system, that may return a value and may take input parameters.

(mathematics) Any function in which each point in the domain maps to just one point in the range