According to the revised 2nd edition of Abbreviations & Acronyms: A Guide for Family Historians by Kip Sperry published in 2003, “drm” means drummer, “stkp” means store keeper, “inv” means investment or inventory, and “Marc” means marriage contract.
This book has a lot of abbreviations and acronyms to assist in genealogy research. For instance you will often see abbreviations in land records such as “adj.” for adjoining, “r.” for River, etc.
The book also contains acronyms. Some are common like DAR (Daughters of the American Revolution) or NARA (National Archives and Records Administration), but there are also other acronyms you might come across such as NAS (no author given in source) and DAC (Daughters of American Colonists.