pri·mo·gen·i·ture
(prī′mō-jĕn′ĭ-cho͝or′)n.1. The state of being the firstborn or eldest child of the same parents.
2. Law The right of the eldest child, especially the eldest son, to inherit the entire estate of one or both parents.
pri′mo·gen′i·tar′y (-jĕn′ĭ-tĕr′ē), pri′mo·gen′i·tal (-təl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
primogenital
(ˌpraɪməʊˈdʒɛnɪtəl) or primogenitive
adjrelating to primogeniture
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014