noun

• Abbreviation of Missus or Mistress (used before an adult woman's name or surname, used for any high-status woman without regard to marital status until the 1800s, after which it began to be reserved for married, divorced and widowed women and used with their married surnames)
• Initialism of Materials Research Society.
• Initialism of Melbourne Rectangular Stadium.
• Initialism of magnetic resonance spectroscopy.
• Initialism of mandibular repositioning splint.
• Initialism of marginal rate of substitution.
• Initialism of metabolic risk score.