GNU Collaborative International Dictionary of English

Found one definition

1.       
   ‖Myelitis (?), n. [NL., from Gr. μυελός marrow + -itis.] (Med.)
   1. Inflammation of the spinal marrow or its membranes.
   
   [1913 Webster]
   
   
   3. Inflammation of bone marrow.
   
   [PJC]