[penguin_booze]

I've bound the keys 'v' and 's' for vertical and horizontal splitting to match Vim's default bindings.

What tmux calls horizontal and vertical splits is inverse of those in Vim - hence -h flag for what most would call as vertical split. I suspect one of the authors was Australian!

[opan]

There is ambiguity in vertical / horizontal split. Does it refer to the "cut" or the result?

In Sway and i3 if I make a vertical split and open a new window, it appears below (thus vertical), but the split was like a cut horizontally across. I've seen some people use the - and | keys for tmux splits which kind of avoids the language issues and turns it into which way the new line is drawn.

[penguin_booze]

I recognize the ambiguity. I tend to think in terms of the result; so, in vim, I do vertical splitting because I want that result where the cleaving line runs vertically.