Meaning of FUNCTIONAL in English

[] adj (1631) 1 a: of, connected with, or being a function b: affecting physiological or psychological functions but not organic structure "~ heart disease"

2: used to contribute to the development or maintenance of a larger whole "~ and practical school courses"; also: designed or developed chiefly from the point of view of use "~ clothing"

3: performing or able to perform a regular function -- n -- adv

Merriam-Webster English vocab.      Английский словарь Merriam Webster.