From Longman Dictionary of Contemporary EnglishMIAMIA /ˌem aɪ ˈeɪ/ noun [countable] American EnglishPMA (missing in action) a soldier who has disappeared in a battle and who may still be alive There are still more than 500 MIAs.
Examples from the Corpus
MIA• They are still occupied by things like MIAs, prisoners of war, refugees, things of the past. 