Definition of "MIA"

(military) Initialism of missing in action.

(by extension) To be absent for a long time.  examples

(Mormonism) Initialism of Mutual Improvement Association.  examples

(military) Initialism of missing in action., a service member that did not return from action and was not found in the field

(Indo-Aryan linguistics) Initialism of Middle Indo-Aryan.  examples

(sports) Abbreviation of Miami.  quotations  examples