Main Entry: fir·ma·ment

Pronunciation: \ˈfər-mə-mənt\

Function: noun

Etymology: Middle English, from Late Latin & Latin; Late Latin firmamentum, from Latin, support, from firmare

Date: 13th century

1 : the vault or arch of the sky : heavens
2 obsolete : basis
3 : the field or sphere of an interest or activity <the international fashion firmament>

— fir·ma·men·tal \ˌfər-mə-ˈmen-t^əl\ adjective