primal
     adj 1: 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" [syn: {cardinal},
             {central}, {fundamental}, {key}]
     2: 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"
        [syn: {aboriginal}, {primeval}, {primaeval}, {primordial}]
Source: WordNet® 2.0