I'm the maker of Stemmy.

Why I built it: looking a word up is easy. Keeping it is the hard part. You read the definition, close the tab, and the word is gone by tomorrow. And a dictionary gives you a wall of senses when you only need the one that fits the sentence in front of you.

So Stemmy does three things:

1. Select a word on any page and see what it means in that sentence, with the general meaning and the word's roots one click away.

2. Save it with the sentence and the page you found it on.

3. Bring it back in short spaced-repetition reviews (FSRS), with your own sentence as the cue. Each button tells you when the word will come back.

Two optional extras: Wallet Letters (beta), a short email with up to three due words and "I remembered / I forgot" links that update your schedule; and Immersirds back into articles you read.