Isn't that is what is referred to at-large, when a representative covers an entire area? I noticed it when looking at Nebraska's Congressional caucus.
Nope, sorry, sir, but "at large" means at large for the whole state, when there's only one congressman, such as in Wyoming or Alaska or Vermont.
For the whole state.
Nebraska has three congressmen representing specific areas--Omaha, Lincoln, and the whole rest of the state.
Of course, "the whole rest of the state" is larger, in territory, than Florida.
During the early 1960s, when the Supreme Court was trying to decide the one-man, one-vote issue for congressional districts, certain corrupt blue states, such as Illinois and New York, in one election had to elect all congressmen at large, until the issue was settled.
It must've been odd in New York, for example, where there were circa 40 House seats, and the whole state had to vote to fill all seats, not just the one from their area.