Func"tion*al (?), a.
1.
Pertaining to, or connected with, a function or duty; official.
2. Physiol.
Pertaining to the function of an organ or part, or to the functions in general.
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.
© Webster 1913.