noun

• The 12th letter of the Modern Greek alphabet.
• (Zen Buddhism) Nothingness; nonexistence; the illusory nature of reality.
• A unit of surface area, currently equivalent to two-thirtieths of a hectare.
• A hypothetical continent that allegedly existed in the Atlantic or Pacific Ocean.
• μ (a mu particle)
• Mu (a river in Burma)
• (Philippines) Relationship where two people like each other and are mutually aware of it, but have yet to have an official romantic relationship.
• (Philippines) Person with which one has such a relationship.
• Abbreviation of North Maluku, a province of Indonesia. [A province of Indonesia.]