If the loop is so big it's scrollable, sure use row, col, etc.

That was my "vast majority" qualifier.

For most short or medium sized loops, though, renaming "i" to something "meaningful" can harm readability. And I don't buy the defensive programming argument that you should do it anyway because the loop "might grow bigger someday". If it does, you can consider updating the names then. It's not hard -- they're hyper local variables.

In a single-level loop, i is just an offset. I agree that depending on the context (maybe even for the vast majority of for loops like you're suggesting) it's probably fine.

But once you nest three deep (as in the example that kicked off this thread), you're defining a coordinate space. Even in a 10-line block, i, j, k forces the reader to manually map those letters back to their axes. If I see grid[j][i][k], is that a bug or a deliberate transposition? I shouldn't have to look at the for clause to find out.