eldest Meaning, Definition & Usage

  1. noun the offspring who came first in the order of birth
    firstborn.
  2. adjective satellite first in order of birth
    firstborn.
    • the firstborn child

WordNet

Eld"est adjective
Etymology
AS. yldest, superl. of eald old. See Elder, a.
Definitions
  1. Oldest; longest in duration. Shak.
  2. Born or living first, or before the others, as a son, daughter, brother, etc.; first in origin. See Elder. "My lady's eldest son." Shak.
    Their eldest historians are of suspected credit. Bp. Stillingfleet.
    R. A. Proctor.

Webster 1913