Entry 2 senses · 2 variants Webster, 1913 Primogenitive · Pri·mo·gen·i·tive · IPA a. n. 01 a. Of or pertaining to primogeniture. 1. Of or pertaining to primogeniture.[R.] 02 n. Primogeniture. 1. Primogeniture.[Obs.] “The primogenitive and due of birth.” — Shak.