The Tetragrammaton (/ˌtɛtrəˈɡræmətɒn/; from Ancient Greek τετραγράμματον (tetragrámmaton) ‘[consisting of] four letters’), or Tetragram, is the four-letter Hebrew theonym יהוה‎ (transliterated as YHWH), the name of the national god of Israel. The four letters, written and read from right to left, are yodh, he, waw, and he. The name may be derived from a verb that means “to be”, “to exist”, “to cause to become”, or “to come to pass”. While there is no consensus about the structure and etymology of the name, the form Yahweh is now accepted almost universally.

The books of the Torah and the rest of the Hebrew Bible except Esther, Ecclesiastes, and (with a possible instance of the short form יה‎ in verse 8:6) the Song of Songs contain this Hebrew name. Observant Jews and those who follow Talmudic Jewish traditions do not pronounce יהוה‎ nor do they read aloud proposed transcription forms such as Yahweh or Yehovah; instead they replace it with a different term, whether in addressing or referring to the God of Israel. Common substitutions in Hebrew are Adonai (“My Lord”) or Elohim (literally “gods” but treated as singular when meaning “God”) in prayer, or HaShem (“The Name”) in everyday speech.