From BiblePortal Wikipedia

Watson's Biblical & Theological Dictionary [1]

the descendants of Ishmael, the son of Abraham by Hagar, his Egyptian bond-maid. Ishmael was born B.C. 1910, and his name, founded on a circumstance which afforded relief to his mother, when she was wandering from her master's house toward Egypt, her native country, is derived from the Hebrew ישמעאל , formed of שמע , to hear, and אל , God, and denoting, "the Lord hath hearkened." The heavenly messenger who appeared to Hagar in the wilderness, and instructed her by what name to call her future son, predicted also that he and his posterity would prove fierce and warlike, engaged in repeated hostilities, and yet able to maintain their independence. Hagar, deriving encouragement from this circumstance, returned to the house of Abraham, and was soon delivered of her promised son. The father regarded Ishmael as the heir of his wealth, till Sarah had the promise of her son Isaac. After the birth of Isaac, Abraham was persuaded by his wife to dismiss Hagar and her son; and the patriarch probably provided for their subsistence in some distant situation, where they could not encroach on the patrimony of Isaac. Having wandered for some time in the wilderness of Beersheba, they proceeded farther to the wilderness of Paran, which bordered on Arabia; and here Ishmael arrived at maturity, and became an expert archer, or a hunter and warrior. In process of time his mother procured for him a wife out of Egypt, by whom he had twelve sons, who eventually established themselves as the heads of so many distinct Arabian tribes. Accordingly, the descendants of Ishmael are mentioned in history under the general name of Arabians and Ishmaelites. Of Ishmael's personal history, we merely learn from the sacred writings, that he joined with his brother Isaac in paying the last tribute of respect to the remains of their father; and that he died at the age of a hundred and thirty-seven years, B.C. 1773,   Genesis 25:9;  Genesis 25:18 . His descendants, according to the Scripture account, spread themselves "from Havilah to Shur, that is, before Egypt, as thou goest toward Assyria." From this brief statement, we may conjecture how far their territory extended; for Havilah, according to the generality of writers, was situated near the confluence of the Tigris and Euphrates, and Shur, on the isthmus which separates Arabia from Egypt, now called the isthmus of Suez. From thence we may well imagine, that they spread themselves on both sides so far as to have taken possession of the greatest part of Arabia; and, indeed, Josephus does not scruple to style their progenitor the founder of the Arabian nation. See Arabia .

International Standard Bible Encyclopedia [2]

ish´mā̇ - el - ı̄ts ( ישׁמעאלים , yishme‛ē'lı̄m ): The supposed descendants of Ishmael, the son of Abraham and Hagar, whom Abraham sent away from him after the birth of Isaac (  Genesis 21:14-21 ). The sons of Ishmael are given in  Genesis 25:13 ,  Genesis 25:14; they were twelve in number and gave rise to as many tribes, but the term Ishmaelite has a broader signification, as appears from  Genesis 37:28 . 36, where it is identified with Midianite. From  Genesis 16:12 it may be inferred that it was applied to the Bedouin of the desert region east of the Jordan generally, for the character there assigned to Ishmael, "His hand shall be against every man, and every man's hand against him," fits the habits of Bedouin in all ages. Such was the character of the Midianites as described in Jdg 7, who are again identified with the Ishmaelites (  Judges 8:24 ). These references show that the Ishmaelites were not confined to the descendants of the son of Abraham and Hagar, but refer to the desert tribes in general, like "the children of the east" ( Judges 7:12 ).