Func"tion*al (?), a. 1.
Pertaining to, or connected with, a function or duty;
2. (Physiol.) Pertaining to the
function of an organ or part, or to the functions in
Functional disease (Med.), a disease
of which the symptoms cannot be referred to any appreciable lesion or
change of structure; the derangement of an organ arising from a
cause, often unknown, external to itself opposed to organic
disease, in which the organ itself is affected.