- firm or solid earth; dry land (as opposed to water or air).
- the solid earth; firm ground
n.c.1600, “part of the Italian mainland ruled by Venice,” from Modern Latin terra firma, literally “firm land,” from Latin terra “earth, land” (see terrain) + firma “firm,” fem. of firmus (see firm (adj.)). Meaning “the land” (as distinct from “the sea”) is first attested 1690s. Dry land, as opposed to the sea: “After our stormy voyage across the Atlantic Ocean, we were relieved to set foot on terra firma.” From Latin, meaning “firm (or solid) ground.”