Primogeniture
/ˌpraɪməʊˈdʒenɪtʃər/
Definition 1 of 2
Pro Tip 1/3Gender Bias
Historically, 'primogeniture' favored males over females in inheritance, reflecting social gender biases. 
Despite having an older sister, under primogeniture, Thomas became the heir to the family business.
Pro Tip 2/3Legal Obsolescence
In modern times, many places have abolished or overridden primogeniture with more equitable inheritance laws. 
Our family respects my grandfather's will, which divides the estate equally, not following primogeniture.
Pro Tip 3/3Cultural Variation
'Primogeniture' varies culturally; some places might still follow this tradition while others have discarded it. 
In Japan, the concept of primogeniture once strongly influenced family businesses and imperial succession.