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

• Functional form and functionalism (architecture) apply to architectural design.
• Functional (mathematics) is a term applied to certain scalar-valued 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 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.
• Functional group in organic chemistry (for example, "This compound has two carbonyl functions").
• Functional classification is a term used in the United States for class of road.

See also

• Function (disambiguation)
• Functionalism
• Functional group (disambiguation)