\Black" let`ter\
The old English or Gothic letter, in which the Early English
manuscripts were written, and the first English books were
printed. It was conspicuous for its blackness. See {Type}.

\Black"-let`ter\, a.
1. Written or printed in black letter; as, a black-letter
   manuscript or book.
2. Given to the study of books in black letter; that is, of
   old books; out of date.
         Kemble, a black-letter man!           --J. Boaden.
3. Of or pertaining to the days in the calendar not marked
   with red letters as saints' days. Hence: Unlucky;
   inauspicious.