The Collaborative International Dictionary of English v.0.48:

Mrs \Mrs.\
   The customary abbreviation of Mistress or Missess when used
   as a title of courtesy, in writing and printing; as, Mrs.
   Clinton is commonly called by her full name, Hillary Rodham
   Clinton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Mrs
    n 1: a form of address for a married woman [syn: Mrs, Mrs.]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

MRS
       Media Recognition System (DAT)


The Free On-line Dictionary of Computing (30 December 2018):

MRS

   Modifiable Representation System.

   An integration of logic programming into Lisp.

   ["A Modifiable Representation System", M. Genesereth et al,
   HPP 80-22, CS Dept Stanford U 1980].

   (1994-11-08)