'Primogenitor' definitions:

Definition of 'primogenitor'

From: WordNet
noun
An ancestor in the direct line [syn: progenitor, primogenitor]

Definition of 'Primogenitor'

From: GCIDE
  • Primogenitor \Pri`mo*gen"i*tor\, n. [LL., fr. L. primus first + genitor a begetter.] The first ancestor; a forefather. [1913 Webster]