noun

• (nautical) M/S: Initialism of motor ship.
• Title used before an adult woman's name or surname, especially when it is not desired or possible to indicate her marital status with Miss or Mrs.
• (plural MSS) Abbreviation of manuscript. [A book, composition or any other document, written by hand (or manually typewritten), not mechanically reproduced.]
• (numismatics) Initialism of mint state, a grading term.
• (pharmacology) Initialism of morphine sulfate.
• (cardiology) Initialism of mitral stenosis.
• (neurology, uncountable) Initialism of multiple sclerosis. [(pathology) A chronic disease of the brain and spinal cord characterized by changes in sensation, visual problems, weakness, depression, difficulties with coordination and speech, impaired mobility and disability.]
• (academics) Initialism of Master of Science. [A degree that usually requires 2-3 years beyond a Bachelor of Science and emphasizes science and scientific applications. The degree is less advanced than a Doctorate degree.]
• Initialism of middle school. [(education, countable) A school which crosses the traditional divide between primary school and secondary school.]
• (philately) Initialism of mini-sheet.
• (criminology) Initialism of murder-suicide. [(criminology) A murder in which the killer subsequently commits suicide.]
• Initialism of Mato Grosso do Sul, a state of Brazil. [A state of the Center-West Region, Brazil. Capital: Campo Grande]
• Initialism of Microsoft: an American multinational technology company founded in 1975. [(trademark) Microsoft Corporation.]
• Abbreviation of Mississippi, a state of the United States of America. [A state of the United States.]
• (chemistry) Abbreviation of mesyl. [(organic chemistry, especially in combination) The univalent radical CH₃SO₂– of methanesulfonic acid.]
• Abbreviation of manuscript. [A book, composition or any other document, written by hand (or manually typewritten), not mechanically reproduced.]