Definition of "mn"

mn¹

numeral
1. (chiefly Britain, Commonwealth except Canada, Ireland) Abbreviation of million.

verb
1. (Internet slang, text messaging) Abbreviation of mean.
  Quotations
  Sure, we may use cellphones and e-mail hundreds of times a week, but we say very little. […] Most of our talk, even in privileged IM circles, is no deeper than the words we exchange with the pizza guy. […] U C wt I mn?
  2008 January–February, Chris Rodell, “Small talk, big results”, in Men's Health, volume 23, number 1, page 80