1To provide with a function or functions; to make functional.
2US To organize (a business or workplace) such that work is distributed according to the specialized function of individual workers or departments; to distribute (work) in this way.
To introduce a functional group into (a molecule, or one of its bonds or atoms) in order to alter the chemical behaviour of the molecule.
To attach molecules or nanoparticles to the surface of (a material) in order to alter its physical or chemical properties.
Mid 19th century; earliest use found in Webster's American Dictionary of the English Language. From functional + -ize.