The micro sign.
More from Tech Symbols.
The quickest way is to copy µ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
µ is U+00B5 (decimal 181).
Use µ in HTML to render µ on a web page.
On Windows you can type it with Alt+181 (hold Alt and enter the number on the numeric keypad).
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