Abbreviation of month(s) old.

(trade) Abbreviation of malicious damage.

(military) Abbreviation of mobilization day.

Alternative form of p.m.

(nautical) Initialism of motor vessel.

(nautical) Initialism of motor ship. – a ship propelled by an internal combustion engine, such as a diesel engine, in contrast to sailing ships and steamships

(Internet slang) Abbreviation of never mind.

Alternative spelling of S&M

(linguistics) Initialism of Merriam-Webster.

Alternative form of M.Eng.