What is the mnemonic for Ctrl-Y (in normal mode)?

Question

I know "expose one more line" for Ctrl-E, but why use Ctrl-Y to expose one more line at the top? Is there an easy mnemonic for this that I'm missing?

Answer 1

Bill Joy and Mark Horton wrote in their original vi manual:

If you want to see more of the file below where you are, you can hit ^E to expose one more line at the bottom of the screen, leaving the cursor where it is. The command ^Y (which is hopelessly non-mnemonic, but next to ^U on the keyboard) exposes one more line at the top of the screen.

So, "next to u" was the motivation, and can serve as a mnemonic, I guess.

The Y also sort of represents an arrow pointing up (↑) if you squint a little bit (it has the head of the arrow inverted).

Answer 2

I like to call <C-y> "Yester-line"™ like "Yesterday". Explaining it along with <C-e> rhymes, too. "Extra-line" and "Yester-line"™.