AnkiApp

What do the self-grade buttons ("Fail", "Hard", "Good", "Easy") mean?

When you review cards in AnkiApp, after seeing the front side of a card and hitting "Flip", you're given 4 options to indicate how well you knew what would be on the back side of a card.

review buttons

This is what those options mean:

Fail When you flipped the card, it wasn't what you expected.
Hard When you flipped the card, it was what you expected, but you weren't sure it would be.
Good When you flipped the card, it was what you expected, but it didn't come to you fluently.
Easy When you flipped the card, it was what you expected, and it came to you fluently.