primogeniture
noun /ˌpraɪməʊˈdʒenɪtʃə(r)/
/ˌpraɪməʊˈdʒenɪtʃər/
[uncountable]- (law) the system in which the oldest son in a family receives all the property when his father dies
- (formal) the fact of being the first child born in a family
Word Originearly 17th cent.: from medieval Latin primogenitura, from Latin primo ‘first’ + genitura ‘geniture’ (a person's birth).