fundamental

Universal Words adjective, noun adjective 1 serious and very important; affecting the most central and important parts of sth: There is a fundamental difference between the two points of view. * A fundamental change in the organization of health services was required. * a question of fundamental importance 2 ~ (to sth) central; forming the necessary basis of sth: Hard work is fundamental to success. 3 [onlybeforenoun] (physics) forming the source or base from which everything else is made; not able to be divided any further: a fundamental particle noun [usuallypl.] a basic rule or principle; an essential part: the fundamentals of modern physics * He taught me the fundamentals of the job.