DuckCorp Dico

Found one definition

1.                 From German - English Ding/FreeDict dictionary ver. 1.9-fd1:
                   
   
   
                   
                     
   diesen Monats /dˌiːzən mˈoːnɑːts/ (d. M. /dˈeː ˈɛm/)
   of the current month, instant [dated] inst.,  /ˈɪnst/
         "am 10. diesen Monats"  - on 10th instant
    see: Ihr Schreiben vom 27. d. M.