Strong’s Greek
G4415 — prototokia
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
πρωτοτόκια
prototokia — pronounced pro-tot-ok'-ee-ah
from 4416; primogeniture (as a privilege):--birthright. see GREEK for 4416
1 occurrence in the KJV.
Hebrews 12:16
Lest there be any fornicator, or profane person, as Esau, who for one morsel of meat sold his birthright.