ter ‧ ra fir ‧ ma /ˌterə ˈfɜːmə $ -ˈfɜːr-/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Latin ; Origin: 'firm land' ]
land, rather than sea or air – used humorously:
We were glad to be back on terra firma.
ter ‧ ra fir ‧ ma /ˌterə ˈfɜːmə $ -ˈfɜːr-/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Latin ; Origin: 'firm land' ]
land, rather than sea or air – used humorously:
We were glad to be back on terra firma.
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012