Mx.

[ miks, muhks ]
/ mɪks, mʌks /

a title of respect prefixed to a person's surname: unlike Mr., Mrs., or Ms., it does not indicate gender and may be used by a person with any or no specific gender identity.

Origin of Mx.

1975–80; M (as in Mr./Mrs./Ms.) + x (symbol for an unknown quantity, person, or thing)