The Masoretic Text (MT) is the Hebrew text of the Jewish Bible (Tanakh). It defines not just the books of the Jewish canon, but also the precise letter-text of the biblical books in Judaism, as well as their vocalization and accentuation for both public reading and private study. The MT is also widely used as the basis for translations of the Old Testament in Protestant Bibles, and in recent decades also for Catholic Bibles.
The MT was primarily copied, edited and distributed by a group of Jews known as the Masoretes between the seventh and tenth centuries CE. Though the consonants differ little from the text generally accepted in the early second century, it has numerous differences of both little and great significance when compared to (extant 4th century) versions of the Septuagint, originally a Greek translation (around 300 BCE) of the Hebrew Scriptures in popular use in Palestine during the common era and often quoted in the second part of the Christian Bible (known as the New Testament).
The Hebrew word mesorah (מסורה, alt. מסורת) refers to the transmission of a tradition. In a very broad sense it can refer to the entire chain of Jewish tradition (see Oral law), but in reference to the masoretic text the word mesorah has a very specific meaning: the diacritic markings of the text of the Hebrew Bible and concise marginal notes in manuscripts (and later printings) of the Hebrew Bible which note textual details, usually about the precise spelling of words.