Mah nishtaneh ha-Layloh hazeh. "What distinguishes this night" (from all other nights); the question introducing the narrative of the Exodus from Egypt in the Seder service of the Passover nights.
Mairev. Evening service.
Malkeh. Queen.
Matzoth. Cakes of unleavened bread.
Melech. King.
Menorah. Candlestick used on Chanukkah or Sabbath.
Meshugge. Crazy.
Meshummed. Apostate.
Mikveh. Ritual bath.
Minchah. Afternoon service.