Functional Style is a system of interrelated language means serving a definite aim in communication. It is the coordination of the language means and stylistic devices which shapes the distinctive features of each style and not the language means or stylistic devices themselves.
Each style, however, can be recoquized by one or more leading features which are especially conspicuous. For instance the use of special terminology is a lexical characteristics of the style of scientific prose, and one by which it can easily be recognized.
A style of language can be fined as a system of coordinated, interrelated and inter-coordinated language means intended to full-fill a specific function of communication and aiming at a defined effect. Style of language is a historical category.