gash'-mu, gash'-moo (gashmu): A form of the name GESHEM (which see), found in Neh 6:6 (compare 6:1), "And Gashmu saith it." According to BDB the same termination -u is found in Nabatean proper names.
Bibliography Information Orr, James, M.A., D.D. General Editor. "Definition for 'GASHMU'". "International Standard Bible Encyclopedia". bible-history.com - ISBE; 1915.