The title in the English text comes from the main character in the second part of the book (chapters 7-10). In the Septuagint translation this book also bore the name of Ezra or Esdras, the Greek transliteration of "Ezra.""Ezra"is a short form of Azariah, which means "Yahweh has helped."The Hebrew Bible has the same title.
Early Hebrew copyists placed Ezra together with Nehemiah because Nehemiah continues the history of Ezra.1Another reason they may have done this was to make the total number of canonical books agree with the number of letters in the Hebrew alphabet.2Another view is that they were written originally as one book and than divided later.3Even today the Hebrew Bible links Ezra and Nehemiah as did the Septuagint translators. However the repetition of Ezra 2 in Nehemiah 6:7-70 suggests that these two books were not originally one. Evidently Origen (third century A.D.) was the first to divide Ezra-Nehemiah into two books, and Jerome followed this precedent in his Latin (Vulgate) translation.4
