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Webster 1913 Edition

Adj.

First born, or first of all; original; primary. See

Adj.

[L. primigenius; primus, first, and genus, kind, or gignor, to beget.] First born; original; primary.

primigenial ‎(not comparable)

First of all, first born, primary, original.
What difference is there, then, between God and primigenial chaos? — Umberto Eco, The Name of the Rose.