'Eldest' in the Bible

Then Adonijah the son of [David’s wife] Haggith exalted himself, saying, “I [the eldest living son] will be king.” So [following Absalom’s example] he prepared for himself chariots and horsemen, and fifty men to run before him.

So he said, “You know that the kingdom belonged to me [as the eldest living son] and all Israel looked to me and expected me to be king. However, the kingdom has passed [from me] and became my brother’s, for it was his from the Lord.