cardinal, central, fundamental, key, primal -- (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")
aboriginal, primal, primeval, primaeval, primordial -- (having existed from the beginning; in an earliest or original stage or state; "aboriginal forests"; "primal eras before the appearance of life on earth"; "the forest primeval"; "primordial matter"; "primordial forms of life")
(Sound)
