eldest

/ˈɛldəst/
adjective
  1. Oldest; used especially to describe the firstborn child in a family or the oldest among a group of siblings.
    • The eldest child often helps take care of the younger ones.
    • My eldest sister is a doctor in Chicago.
    • He is the eldest of three brothers.
noun
  1. The oldest person in a group, especially the oldest child in a family.
    • The eldest usually gets the largest bedroom in the house.
    • In many cultures, the eldest inherits the family business.
    • As the eldest, she felt responsible for her younger siblings.
Synonyms
What does "eldest" mean? | whatsthatwordmean | whatsthatwordmean