Pronunciation: (fungk'shu-nl),[key] —adj. 1. of or pertaining to a function or functions: functional difficulties in the administration. 2. capable of operating or functioning: When will the ventilating system be functional again? 3. having or serving a utilitarian purpose; capable of serving the purpose for which it was designed: functional architecture; a chair that is functional as well as decorative. 4. Also,func'tion•al•is'tic.(of a building or furnishing) constructed or made according to the principles of functionalism or primarily as a direct fulfillment of a material need.
5. Med.without a known organic cause or structural change: a functional disorder. Cf. organic (def. 5).
6. pertaining to an algebraic operation: a functional symbol. 7. Ling.(of linguistic analysis, language teaching, etc.) concerned with the communicative role of language rather than, in addition to, or as the framework for its formal structure.
—n. Math.a function that has a domain whose elements are functions, sets, or the like, and that assumes numerical values.