fundamental

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"

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"

the lowest tone of a harmonic series