# The words behind a private memory.

This glossary defines the terms used across Earlyn's site and app, from screen memory and OCR to MCP, speaker diarization and word error rate, in one sentence each.

## Screen memory

A searchable record of what was on a computer's screen, kept as pictures and the text read from them. [More](https://www.earlyn.app/features/rewind).

## Moment

In Earlyn, one stored record: a picture of the screen, the text read from it, the app, the window title, the web address and the time. [More](https://www.earlyn.app/features/rewind).

## OCR (optical character recognition)

Reading text from a picture. Earlyn uses Apple's on-device Vision framework when an app exposes no text through Accessibility. [More](https://www.earlyn.app/research/screen-memory-storage).

## Accessibility API

The macOS interface that lets assistive software read the text and structure of windows. Earlyn uses it to read exact on-screen text, never from password fields.

## Semantic search

Finding results by meaning rather than by matching words, by comparing vectors (embeddings) of the question and the stored text. [More](https://www.earlyn.app/research/local-semantic-search).

## Embedding

A list of numbers that represents the meaning of a text; texts with similar meanings have similar embeddings.

## On-device model

An AI model that runs on your own computer, so the question and the data never leave it.

## MCP (Model Context Protocol)

An open protocol that lets AI assistants such as Claude Code call tools; Earlyn ships a local MCP server so agents can search your memory. [More](https://www.earlyn.app/features/ai-agents).

## Speaker diarization

Telling apart who spoke when in a recording. Earlyn does it on the Mac from voice characteristics. [More](https://www.earlyn.app/features/meetings).

## Word error rate (WER)

The share of words a transcription gets wrong: substitutions, deletions and insertions divided by the number of reference words. [More](https://www.earlyn.app/research/turkish-meeting-transcription).

## SQLCipher

An encrypted edition of the SQLite database. Earlyn's database is a SQLCipher file opened with a random 256-bit key from the keychain. [More](https://www.earlyn.app/features/privacy).

## AES-GCM

An authenticated encryption method: it keeps data secret and detects tampering. Earlyn seals screen pictures and meeting audio with it. [More](https://www.earlyn.app/features/privacy).

## Redaction

Replacing secrets such as API keys, tokens or card numbers with a placeholder before anything is stored.

## Retention window

How long memories are kept before they are deleted automatically: the trial week, or 90 days on Pro.

## Skill (SKILL.md)

A Markdown file of instructions an AI coding agent loads for a task. Earlyn writes skills from your work and offers reviewed ones in its Skills Market. [More](https://www.earlyn.app/features/ai-agents).

## Daily digest

A short written summary of the previous day that Earlyn produces each morning from your screen and meeting history. [More](https://www.earlyn.app/features/life-and-library).

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Canonical: https://www.earlyn.app/glossary · Updated 2026-10-02