(1):

(a.) Originally or earliest formed in the growth of an individual or organ; as, a primordial leaf; a primordial cell.

(2):

(n.) A first principle or element.

(3):

(a.) Of or pertaining to the lowest beds of the Silurian age, corresponding to the Acadian and Potsdam periods in American geology. It is called also Cambrian, and by many geologists is separated from the Silurian.

(4):

(a.) First in order; primary; original; of earliest origin; as, primordial condition.