In tomato, for example, the first sepal primordium is formed as an outgrowth at the periphery of the apex and the subsequent sepal primordia are initiated in a helical fashion at an angle of approximately 137° from the previous one.
Source: wiktionary
It is thus vain to hope that the history of the primordia can be reduced to the progress of archeological investigation.
Source: wiktionary
Attempts have been made by historians of religion to distinguish between mythic orientations in time concerned with the repetition of a primordium and those concerned with the anticipation of an eschaton.
Source: wiktionary
[Joseph Smith] did not think of himself as going back to a primordium of true Christianity, as the Puritans did. In his view, there never was a golden age when religion flourished to perfection.
Source: wiktionary