Why Abram was known as Abram the HEBREW?

[tonychanyt]

Genesis 14:

13a One who had escaped came and told Abram the Hebrew, who was living by the oaks of Mamre the Amorite, brother of Eshcol and of Aner.

Strong's Hebrew: 5680. עִבְרִי (Ibri) — 34 Occurrences

Strong's Concordance:

Ibri: perhaps descendant of Eber

Abram was a descendant of Eber (Genesis 11:10-26).

Brown-Driver-Briggs:

used to distinguish Israel from foreigners (= one from beyond, from the other side, i.e. probably (in Hebrew tradition) from beyond the Euphrates

Joshua 24:

2 And Joshua said to all the people, “Thus says the LORD, the God of Israel, ‘Long ago, your fathers lived beyond the Euphrates, Terah, the father of Abraham and of Nahor; and they served other gods.

Abram was called the Hebrew due to his lineage from Eber and geographic origin from beyond the river.