from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The relative molecular mass of a molecule.
- abbr. An abbreviation of mister, a title used before the surname in theory, though not generally in practice, above some undefined social level, too old to be addressed as “Master”, not a knight or of some higher rank, and, in Britain though not in the United States, not entitled to be addressed as “Dr”.
- abbr. March
Abbreviation of Mister. (Wiktionary)