primogeniture (n.)youdaoicibaDictYouDict[primogeniture 词源字典]
"right of succession of the first-born," c. 1600, from French primogeniture and directly from Medieval Latin primogenitura, from Late Latin primogenitus "first-born," from Latin primo (adv.) "first in order of time," from primus "first" (see prime (adj.)) + genitus, past participle of gignere "to beget" (see genus). Earlier it meant simply "fact of being first-born" (1590s).[primogeniture etymology, primogeniture origin, 英语词源]