μι — meaning in English mi Greek → English · translate English → Greek instead English meaning mi noun In solfège (do-re-mi), the syllable used for the third note of a major musical scale. mu noun The twelfth letter of the Greek alphabet (Μ, μ). Senses μι is used for these senses in English: mi (music) A syllable used in sol-fa (solfège) to represent the third note of a major scale. mu The 12th letter of the Modern Greek alphabet.