firstborn

first·born  (fûrstbôrn)

adj.

First in order of birth; born first.

n.

The child in a family who is born first.

Thesaurus

Noun	1.	firstborn - the offspring who came first in the order of birth eldest offspring, progeny, issue - the immediate descendants of a person; "she was the mother of many offspring"; "he died without issue"
Adj.	1.	firstborn - first in order of birth; "the firstborn child" eldest first - preceding all others in time or space or degree; "the first house on the right"; "the first day of spring"; "his first political race"; "her first baby"; "the first time"; "the first meetings of the new party"; "the first phase of his training"