Generally, functional refers to something able to fulfill its purpose or function.

• Functional (mathematics) is a term applied to functions in mathematics, computer science, and Lagrangian mechanics.
• Functional (ontology) refers to a property or relation in an ontology that can only hold a single value for a given individual.
• Functional programming is used in computer science as well.
• Functional form and functionalism (architecture) apply to architectural design.
• Functional symptom is sometimes used in medicine to describe symptoms that have no current visible organic basis, e.g. if they are a result of psychological or perceptual dysfunction. Historically functional symptoms tend to be reclassified as organic as investigative techniques improve.
• Diatonic functionality describes a music term.

See also

• Functionalism