functional programming; FP
scientific calculator; scientific electronic calculator
probability density function
built-in function (e.g. in programming language)
real-valued function; real function
propositional (sentential) function
circular function; trigonometric function
saving function; savings function
transformational function
multivalued function; multiple-valued function
monotone function; monotonic function
identity function; identity operator
immediately invoked function expression (in JavaScript); IIFE
arrow function (in JavaScript)