eldest
n. US //ˈɛɫdəst// UK //ˈɛldəst// el·dest
-
1 the first-born person (n.) B2 Upper Intermediatethe child who was born first in a family.
the individual possessing the greatest seniority by birth within a family unit.
ExampleAs the eldest, she often had to look after her younger brothers.
ExampleThe inheritance was traditionally reserved for the eldest, a custom that frequently created friction among the younger siblings.
UsageOften functions as a substantive noun preceded by 'the'.
- first born