RSM abbreviation for regimental sergeant major Royal School of Music Royal Society of Medicine San Marino (international car registration) Liberaldictionary.com
Word Origin for RSM (sense 4) From R(epublic of) S(an) M(arino) Collins English Dictionary – Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012