bal

noun1

1. •
   The surface of a mine.

   • The surface of the mine is called the bal, and every level and shaft has a name. — 1856

adjective1

1. •
   Abbreviation of bald (no hair).

noun2

1. •
   Initialism of broad absorption line or broad absorption line trough.
2. •
   Initialism of biphenotypic acute leukaemia.