fundamental

nouns

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"
is a type of (narrower)
anything that contributes causally to a result
"a number of factors determined the outcome"
the lowest tone of a harmonic series

adjectives

serving as an essential component
"a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument"; "computers are fundamental to modern industrial structure"
being or involving basic facts or principles
"the fundamental laws of the universe"; "a fundamental incomatibility between them"; "these rudimentary truths"; "underlying principles"
far-reaching and thoroughgoing in effect especially on the nature of something
"the fundamental revolution in human values that has occurred"; "the book underwent fundamental changes"; "committed the fundamental error of confusing spending with extravagance"; "profound social changes"