The mic.
Speak, photograph, or type. Recognition runs on the phone, so a word you meet on a plane resolves exactly as fast as one you meet at home.
Voice · Camera · Keyboard
Say it.
Keep it.
Know it.
01 — What it is
A reading companion for the words you don't know yet.
Say a word out loud and the definition is already there. No signal, no sign-in, no tab to switch to — Moonlight files it under the book you were reading and brings it back when you're closest to forgetting it.
02 — The loop
One word, from the page to the long term.
Three screens, in the order you actually use them — catch the word where you met it, file it under what you were reading, and meet it again before it goes.
The bank.
Every word is filed under the book you were reading when you met it, so the list reads like a record of what you've been doing, not a pile of flashcards.
WordNet 3.1, bundled offline
The recall.
A short quiz picks the words you're closest to forgetting. Canonical SM-2 scheduling — the same algorithm the serious review apps are built on.
SM-2 spaced repetition
03 — The word map
Your vocabulary, seen from the outside.
Everything you've saved, laid out as a sphere you can turn. Words from the same book pull together; the ones you've mastered wear a ring. Drag it.
40 words · 4 shelves
Brightness is the book.
Moonlight's default theme has no hues to hand out, so shelves separate on a brightness ramp instead of colour — and colour stays free to mean something else.
A ring means mastered.
Mastery used to recolour the word outright, which made the brightest things on screen a scatter of finished words. As a ring it still reads at a glance, and the eye goes back to the clusters.
Nothing here is a chart.
The map is for noticing, not measuring — that one book gave you nine words in a week, or that a shelf you thought you'd finished is still half unlearned.
Map legend
Current book12
Earlier shelves21
Unfiled7
Mastered9
04 — Specification
No account. No analytics. No catch.
The short version, for anyone who would rather know exactly what they are installing before they install it.
- Definitions
- Princeton WordNet 3.1 — 86,811 headwords bundled, plus Apple's dictionaries when iOS has the word
- Capture
- Voice, camera text, or keyboard
- Review
- SM-2 spaced repetition, scheduled per word
- Your data
- Stored on the phone. There is no Moonlight server.
- Network
- Only to find a book's cover and page count
- Requires
- iPhone, iOS 26 or later. Portrait.
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05 — Availability
Every word you meet is worth keeping.
Moonlight is finishing up for the App Store. It will be an iPhone app, it will work on a plane, and it will not ask you to make an account.