DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Gumma \Gum"ma\ (g[u^]m"m[.a]), n.; pl. Gummata. [NL. So called
      from its gummy contents See Gum.] (Med.)
      A kind of soft tumor, usually of syphilitic origin.
      [1913 Webster]