Eleazar m. Hebrew אֶלְעָזָר 'God has helped'.
The name of a number of Biblical characters, one of the Maccabean martyrs, a 4th C martyr, a 5th C French saint, a 5th C Italian saint, a 9th C Byzantine saint, a 14th C Serbian prince, and a 15th C Serbian prince. Wycliffite Bible (1395): Eleazar, Lazarus.
Lazarus is the Latinized form. Most commonly, Eleazar is used to refer to the Old Testament figures, while Lazarus refers to the New Testament figure.