Useful; serving a purpose, fulfilling a function
Having semantics defined purely in terms of mathematical functions, without side-effects.
Only for functional purposes, notably in architecture
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.
In good working order.
A function that takes a function as its argument; More precisely: A function whose argument varies in a space of (real or complex valued) functions and whose value belongs to a monodimensional space. An example is the definite integration of integrable real functions in a real interval.
A scalar-valued linear function on a vector space.
An object encapsulating a function pointer (or equivalent).
That operates to produce an effect.
Any of a class of behaviors that produce consequences by operating (i.e., acting) upon the environment.
An operative person or thing.