fundamental

far-reaching and thoroughgoing in effect especially on the nature of something

“the fundamental revolution in human values that has occurred”

being or involving basic facts or principles

“the fundamental laws of the universe”

the lowest tone of a harmonic series

serving as an essential component

“an example that was fundamental to the argument”

any factor that could be considered important to the understanding of a particular business

“fundamentals include a company's growth, revenues, earnings, management, and capital structure”