Fundamental
(noun) (usually in the plural) A leading or primary principle, rule, law, or article, which serves as the groundwork of a system; an essential part Example: "one of the fundamentals of linear algebra"
4 QUOTES
(noun) (usually in the plural) A leading or primary principle, rule, law, or article, which serves as the groundwork of a system; an essential part Example: "one of the fundamentals of linear algebra"