From BiblePortal Wikipedia

Smith's Bible Dictionary [1]

O'mar. (Eloquent, Talkative). Son of Eliphaz, the first-born of Esau.  Genesis 36:11;  Genesis 36:15;  1 Chronicles 1:38. (B.C. 1750).

Hastings' Dictionary of the Bible [2]

OMAR (perhaps = ‘eloquent’). A grandson of EsauGenesis 36:11;   Genesis 36:15 ,   1 Chronicles 1:36 ).

Morrish Bible Dictionary [3]

Son of Eliphaz, a son of Esau.  Genesis 36:11,15;  1 Chronicles 1:36 . The name is supposed to survive in the Amir tribe of Arabs.

Fausset's Bible Dictionary [4]

Son of Eliphaz, Esau's firstborn ( Genesis 36:11-15). Related to the Amir Arabs E. of Jordan, also to amar "to speak," and emir "a chief."

Holman Bible Dictionary [5]

 Genesis 36:11 36:15 1 Chronicles 1:36

Hawker's Poor Man's Concordance And Dictionary [6]

Son of Eliphaz, ( Genesis 36:11) from Aumai, he that speaks.

Easton's Bible Dictionary [7]

 Genesis 36:11-15

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [8]

(Heb. Omar', אוֹמָר , Eloquent; Sept. ᾿Ωμάρ ) , the second named of the seven sons of Eliphaz, son of Esau ( Genesis 36:15 [comp.  Genesis 36:11];  1 Chronicles 1:36), who were heads and princes of tribes among the Edomites. B.C. cir. 1900. The name is supposed to survive in that of the tribe of Amir Arabs east of the Jordan. Bunsen asserts that Omar was the ancestor of the Bene Aammer in Northern Edom ( Bibelwerk,  Genesis 36:11), but the names are somewhat different ( א initial, and the Arabic equivalent of ע ).

International Standard Bible Encyclopedia [9]

ō´mar ( אומר , 'ōmār , connected perhaps with 'āmar , "speak"; Septuagint Ωμάν , Ōmán or Ωμάρ , Ōmár ): Grandson of Esau and son of Eliphaz in   Genesis 36:11;  1 Chronicles 1:36; given the title "duke" or "chief" in  Genesis 36:15 .

The Nuttall Encyclopedia [10]

The successor of Abu-Bekr, and the second Caliph from 634 to 644; was at first a persecutor of the Faithful, but underwent in 615 a sudden conversion like Said, with a like result; was vizier of Abu-Bekr before he succeeded him; swept and subdued Syria, Persia, and Egypt with the sword in the name of Allah, but is accused of having burned the rich library of Alexandria on the plea that it contained books hostile to the faith of Islam; he was an austere man, and was assassinated by a Persian slave whose wrongs he refused to redress.