Webster's Revised Unabridged Dictionary · 1913

firstborn

firstborn (fẽrst"bôrn`) , noun

The first child born to a parent; as, his firstborn was showered with gifts from relatives.

Firstborn (fẽrst"bôrn`) , adjective

First brought forth; first in the order of birth; eldest; hence, most excellent; most distinguished or exalted; as, the firstborn child.