Lexical Definition

‎מְגַמָּה‎ mᵉgammâh (meg-am-maw') horde ^H:N-F
from the same as ‎גַּם‎

sup up.

• properly, accumulation, i.e. impulse or direction

1) meaning uncertain; perhaps hordes, accumulation, assembling, eagerness (of Babylonians)

Brown-Driver-Briggs

[‎מְגַמָּה‎] noun feminine Hab 1:9 (of the Chaldaeans) ‎מְגַמַּת פְּנֵיהֶם קָדִ֑ימָה‎, of uncertain meaning: Ges the assembling of their faces is (directed) forwards; Ew De Ke eagerness, comparing (questionably) ‎גָּמָא‎ swallow Job 39:4, and (Frey) seek (whence St proposes ‎מְגֻמַת‎). Text probably erroneous.

Brown-Driver-Briggs References