How do you pronounce MU or μ?

The Greek letter μ is pronounced "mee."

Ancient Greek pronunciation: [my:] or "mee"

Modern Greek pronunciation: [mi] as in mill

Common English pronunciation: [myoo] as in mutation

Measurement pronunciation: "micro-" (example: µm is pronounced "micrometre")

When this letter is used in a Greek word, it makes the same sound as the latin "m"