Useful; serving a purpose, fulfilling a function (adjective)
Only for functional purposes, notably in architecture (adjective)
Having semantics defined purely in terms of mathematical functions, without side-effects. (adjective)
Of a disease, such that its symptoms cannot be referred to any appreciable lesion or change of structure; opposed to organic disease, in which the organ itself is affected. (adjective)
A function that takes a function as its argument; More precisely: A function y=f(x) whose argument x varies in a space of (real valued, complex valued) functions and whose value belongs to a monodimensional space. An example: the definite integration of integrable real functions in a real interval. (noun)
(functional analysis) A scalar-valued linear function on a vector space (noun)
An object encapsulating a function pointer (or equivalent). (noun)
Examples of word functional
"You've probably heard of the term functional MRI," she said.
In this paper, the term functional ingredients refers to substances purported to improve bodily functioning that are added to traditional foods through a manufacturing or other process.
It is important here that I clarify how I am using the term functional in this context.
You probably noticed that the term functional programming has appeared in many areas recently - the C# 3.0 and LINQ have been largely influenced by this paradigm and many of the libraries that enable and simplify writing parallel code rely on functional ideas.
The first time I heard the term functional construction was when I was writing the LINQ to XML section of my book LINQ Unleashed: for C# from Sams.