形容詞 primal:

1. serving as an essential component
   同義詞：cardinal, central, fundamental, key
2. having existed from the beginning; in an earliest or original stage or state
   同義詞：aboriginal, primeval, primaeval, primordial

pri.mal

adj.（形容詞）
Being first in time; original; primeval.
最初的，原始的；遠(yuǎn)古的
Of first importance; primary.
最重要的；主要的

來源：
Medieval Latin prom3lis
中世紀(jì)拉丁語 prom3lis
from Latin promus [first] * see per
源自 拉丁語 promus [最初，首先] *參見 per

【引伸】
primal.ity