Adonai (Hebrew: אֲדֹנָי)
Jews use the word Adonai, Hebrew for "Lord" (Hebrew: אֲדֹנָי), in place of the word G-d on occasion. Formally, this is plural ("my Lords"), but the plural is usually construed as a respectful, and not a syntactic plural.
Since pronouncing G-d’s name or Yud, Hey, and Vav, Hey (Hebrew: ה,ו and ה,י - also designated with the Tetragrammaton YHWH), is avoided out of reverence for the holiness of the name, Jews use Adonai instead in prayers, and colloquially would use Hashem ("the Name").
When the Masoretes added vowel pointings to the text of the Hebrew Bible around the eighth century CE, they gave the word YHWH the vowels of Adonai, to remind the reader to say Adonai instead. Later Biblical scholars mistook this vowel substitution for the actual spelling of YHWH and interpreted the name of God as Jehovah.