Sometimes you use a tool for years and still have something new to learn. I'm talking about vi(1), not vim or nvim, but nvi! (the OpenBSD ones at least.)

While I was reading NetBSD desktop pt.6 "vi(1) editor, tmux and unicode $TERM"

I knew vim end emacs had abbreviations, but I never thought that vi has them too.

Now my ~/.nexrc is more rich:

ab #d #define
ab #i #include