Omahas
a tribe of North American Indians living in E. Nebraska. They number about 1,400. The name is derived from an Indian word meaning "those who go up the stream, or against the current."
OMBAY OMAR I., Caliph of the Mussulmans, the successor of Abu-Bekr, and fatherin-law of Mohammed. He began his reign A. D. 634, and is conspicuous among the conquerors who chiefly contributed to the spread of Ilsamism. His generals drove the Greeks out of Syria and Phœnicia; and the Caliph himself took possession of Jerusalem in 638, till it was reconquered by Godfrey of Bouillon, at the end of the 11th century. Amru, one of his generals, defeated the troops of Heraclius, near Antioch, in 641. Memphis and Alexandria surrendered; all Egypt and a part of Libya were conquered from the Romans; and the famous library, which had been founded at Alexandria by Ptolemy Philadelphus, is said to have been burnt by the express order of Omar I. Having fixed his residence at Medina, he was there assassinated by a Persian slave, in the 10th year of his reign, A. D. 643. He refused to appoint a successor; and thus the caliphate became elective. He introduced the system of standing armies, and a police force.