Glossary

The terms and abbreviations these docs use, each in a sentence, with a link to its specification where it has one and to the page that uses it most. The specifications' versions and status are in standards.md.

Solid and the web

ACL (access control list): the document that says who may read or write a resource on a pod that uses WAC. Specification.
ACP (Access Control Policy): one of Solid's two ways for a pod to say who may read or write a resource; the other is WAC. Specification. Used when a release is made public (standards.md).
ACR (Access Control Resource): the document that says who may read or write a resource on a pod that uses ACP; what an ACL is for WAC. Specification; data-model.md.
CSP (Content Security Policy): a list of what a page may load and run, which the browser enforces. Specification; markdown.md.
DPoP (Demonstrating Proof of Possession): ties a login's tokens to a key the browser holds, so a stolen token is of no use elsewhere. RFC 9449.
IdP (identity provider): the server you log in with, which tells apps that you own your WebID. Also called the OIDC issuer. authentication.md.
IndexedDB: a database inside the browser. A guest's pod is kept in it. Specification; guest-mode.md.
LDP (Linked Data Platform): the rules for containers (folders) of linked data on a server, which a Solid pod follows. Specification.
OIDC (OpenID Connect): a standard way to log in with an account from another site. Specification.
Pod: your own store of data on a Solid server, which you control and which apps read and write with your permission. Solid Memo keeps everything you study in yours. data-model.md.
Solid: a set of open specifications for storing your data in a pod you choose, apart from the apps that use it. solidproject.org; architecture.md.
Solid-OIDC: how Solid apps log you in, OpenID Connect with your WebID. Specification; authentication.md.
Type index: a document in your pod that lists where each kind of data is, so an app can find it; a private one for you alone and a public one. Specification; data-model.md.
WAC (Web Access Control): one of Solid's two ways for a pod to say who may read or write a resource, with .acl documents. Specification.
WCAG (Web Content Accessibility Guidelines): W3C's rules for making web pages usable by everyone, people with disabilities included. Solid Memo aims at version 2.2, level AA. Specification; accessibility.md.
WebID: a web address that names you, such as https://alice.example/profile/card#me. Its document, your profile, says where your pod and your identity provider are. Specification; authentication.md.

Linked data

Data theme: one of the European Union's broad subjects for data sets, from its data theme table, such as EDUC (Education, culture and sport), which every library deck states. Table; deck-library.md.
DCAT (Data Catalog Vocabulary): W3C's terms for describing data sets and catalogs. A deck is described with it. Specification; deck-library.md.
DCAT-AP (DCAT Application Profile): the European Union's rules for using DCAT, which the deck library is checked against. Specification; validation.md.
IRI: a web address used as a name in linked data, which may hold characters beyond ASCII.
JSON-LD: linked data written as JSON. A deck can be saved as a JSON-LD file. Specification; data-model.md.
Profile (of a vocabulary): extra rules for using a vocabulary, such as DCAT-AP for DCAT. Not to be confused with a WebID profile.
PROV-O: W3C's terms for saying where something came from and how it was made. A release says it of itself. Specification; deck-library.md.
RDF (Resource Description Framework): data as statements of subject, predicate and object, each named by an IRI. All of Solid Memo's data is RDF. Specification.
schema.org: a vocabulary search engines read. Solid Memo uses its terms for courses. schema.org; courses.md.
SHACL (Shapes Constraint Language): a language for the shape data must have, such as "a card has one front". Solid Memo's shapes are in ns/shapes/. Specification; shapes.md.
Shape: one SHACL description of a kind of subject, such as a card, at one version. shapes.md.
SKOS (Simple Knowledge Organization System): W3C's terms for lists of concepts, such as the study directions or the topics. Specification; vocab.md.
Turtle: a plain-text way to write RDF, which Solid Memo writes every document in. Specification.
Vocabulary: a set of terms for linked data. Solid Memo's own is in ns/vocab/, prefix sm:. vocab.md.

Text and languages

BCP 47: the standard for language tags such as en, sv or pt-BR. Specification; vocab.md.
CJK: Chinese, Japanese and Korean, written without spaces between some words, which matters for where Markdown emphasis ends. markdown.md.
CLDR (Unicode Common Locale Data Repository): data on how each language writes numbers, dates and plurals. The app's plural messages follow its plural rules. CLDR; i18n.md, policy.md.
CommonMark: a precise specification of Markdown. Specification; markdown.md.
GFM (GitHub Flavored Markdown): GitHub's extensions to CommonMark. Solid Memo takes only its tables. Specification; markdown.md.
Hangul: the Korean alphabet. Its letters are written together in syllable blocks, such as 한.
Jamo: the single letters of Hangul, such as ㅎ, ㅏ and ㄴ. A syllable can be stored as one character or as its jamo, which look the same but are different text; see NFC.
Locale: a language the app's own text is shown in, such as en or ko. i18n.md.
Markdown: a plain-text way to write headings, emphasis, lists and tables. markdown.md.
NFC (Normalization Form C): the Unicode form in which each letter is stored composed, "é" as one character rather than "e" and an accent. The deck library's text must be in it. Specification; deck-library.md.

Spaced repetition

Answer log: the record of every answer, kept in your pod, which the statistics are drawn from. data-model.md.
Answer scale: the buttons you grade an answer with, the full 0 to 5 or Again, Hard, Good and Easy. srs.md.
Desired retention: the chance of recalling a card when it comes back that FSRS-6 schedules for, from 70% to 97%, 90% by default; set in the preferences. srs.md.
Difficulty: FSRS-6's measure of how hard a card is, from 1 (easiest) to 10 (hardest); the harder, the slower its stability grows. srs.md.
Ease factor: SM-2's measure of how easy a card is; the interval grows by it. It starts at 2.5 and never goes below 1.3. srs.md.
FSRS-6 (Free Spaced Repetition Scheduler, version 6): the scheduling algorithm Solid Memo recommends, and a new instance starts on, by Jarrett Ye and the Open Spaced Repetition project; it schedules each review for when the chance of recall falls to the desired retention. The Algorithm; srs.md, policy.md.
Grade (quality): how well you knew an answer, from 0 (blackout) to 5 (perfect). srs.md.
Interval: the number of days until a card is due again.
Lapse: a review forgotten: an answer graded below 3 to a card already introduced, its first that study day, recalled and graded (not a course answer). Every grade below 3 starts the card's repetitions over, but only these are counted. srs.md, statistics.md.
Leech: a card with four lapses or more, in either direction, which the Studio points out. studio.md.
Prompt: one card seen from one side, front to back or back to front, scheduled on its own. srs.md.
Retrievability: the chance, under FSRS-6, of recalling a card now: 90% after as many days as its stability, falling as days go by. srs.md.
Review state: what Solid Memo knows of a prompt's schedule: its ease factor, interval, repetitions and due day; under FSRS-6, also its stability and difficulty, in a state of its own. srs.md.
Scheduler: the algorithm that sets the due days, FSRS-6 or SM-2, chosen in the preferences or from the deck list's invitation to switch. srs.md.
Scheduler invitation: the deck list's offer, to a learner on SM-2, to switch to FSRS-6; "Not now" is kept in the preferences. srs.md.
SM-2 (SuperMemo 2): the scheduling algorithm Solid Memo used alone before FSRS-6, and still uses for an instance made before then until its learner switches, published by Piotr Woźniak in 1990. Description; srs.md, policy.md.
Stability: FSRS-6's measure of how long a card's memory lasts: the days until the chance of recalling it falls to 90%. srs.md.
SRS (spaced repetition system): software that shows you a card just before you would forget it, at longer and longer intervals. srs.md.
Study day: a day as the schedule counts it, which ends at 4 in the morning by default, not at midnight. srs.md.

Code and tools

Adapter: code that connects the app to something outside it, such as a pod or the browser's storage, behind a port. architecture.md.
Biome: the tool that formats and lints the TypeScript, JSON and CSS. biomejs.dev; style.md.
CI (continuous integration): the checks GitHub Actions runs on every pull request and every push to main. A change is merged only when they pass. testing.md.
ci-ok: the one CI check a merge to main waits for, which passes only when every other job passed. testing.md.
commitlint: the tool that checks that a commit message follows Conventional Commits. CI runs it on a pull request's commits. commitlint.js.org; CONTRIBUTING.md.
Composition root: the one place where the layers meet, the composition package. It puts each adapter behind its port and gives the app its use cases. architecture.md.
Conventional Commits: a format for commit messages, type(scope): subject, whose type says what kind of change it is, such as feat or fix, so that a program can read it. conventionalcommits.org; CONTRIBUTING.md.
Deploy key: an SSH key that gives access to one repository alone. The release pushes its commit and tag to main with one. releasing.md.
Docker: runs a program in a container of its own, apart from the rest of the computer. The end-to-end tests and the user journeys start their Solid servers in it. docker.com; testing.md.
DOI (Digital Object Identifier): a lasting name for a published work, such as 10.5281/zenodo.23351087, which https://doi.org/ turns into a link to it. Zenodo gives each release one. doi.org; releasing.md.
End-to-end test (e2e): a test of the app's use cases and Solid adapters against real Solid servers, in e2e/pod/. testing.md.
Environment: a GitHub setting that a job of a workflow names, and that lets it run only on the branches it allows: github-pages, to deploy the site, release, whose secret is the release's deploy key, and labour-market-deck, whose secret is the taxonomy app's key, all three for main alone. releasing.md, deck-library.md.
ETag: a server's tag for one version of a document, which changes whenever the document does. The app sends it back, so that it does not write over a newer version or read again what it already has. RFC 9110; migrations.md.
Hexagonal architecture (ports and adapters): a layout in which the core of the app knows only ports, and adapters connect them to the world outside, so each part can be replaced or tested alone. architecture.md.
Node.js: runs JavaScript outside the browser. The site is built and tested with version 24, as .nvmrc says. nodejs.org; README.
npm: the package manager that comes with Node.js. It installs the dependencies and runs the scripts in package.json, such as npm run check. npm Docs; testing.md.
Port: an interface the core of the app defines for something it needs from outside, such as storing a deck. An adapter implements it. architecture.md.
pySHACL: a SHACL engine written in Python. CI uses it to check what Solid Memo publishes a second time, apart from the engine the browser runs. pySHACL; validation.md.
REUSE: rules from the Free Software Foundation Europe for stating every file's copyright and license so that a program can read them. reuse.software; style.md.
semantic-release: the tool that releases each version: it chooses the number from the commits' Conventional Commits types, writes the changelog, tags the commit and makes the GitHub release. semantic-release's docs; releasing.md.
SemVer (Semantic Versioning): version numbers of the form MAJOR.MINOR.PATCH, where the part that goes up says what kind of change it is. semver.org; releasing.md.
SPDX: a standard list of short license names, such as MIT, and the header that names a file's license with one (SPDX-License-Identifier: MIT). SPDX License List; style.md.
Turborepo: the tool that runs each workspace package's tasks in the right order, and remembers results it can reuse. turborepo.com; architecture.md.
Use case: one thing the app does for its user, such as recording an answer. The UI reaches the rest of the app only through them. architecture.md.
User journey: a test that uses the built app in a browser as a person would, step by step. testing.md.
Vite: the tool that builds the site, and serves it while you work on it (npm run dev). vite.dev; configuration.md.
Workspace package: one of the npm packages the repository is made of, each a layer with its own package.json, such as packages/ui/. architecture.md.

Solid Memo's own terms

Catalog (catalog.ttl): the document that lists an instance's decks, or the deck library's index of its decks. The published shapes and vocabulary, which never change, keep its British spelling in their text. data-model.md.
Course: a library deck with chapters and steps that teach before they ask. courses.md.
Deck: a set of cards studied together. data-model.md.
Deck library: the ready-made decks in decks/, published with the site. deck-library.md.
Digest: a document in the instance that remembers what Solid Memo learned of the others, so a visit can skip what has not changed. data-model.md.
Distractor (wrong option): a wrong answer a course offers beside the right one. courses.md.
Draft: a deck or course being written in the Studio, before it is published as a release. studio.md.
Format version: the version of the shape a document is written in. The app brings older documents up to the one it writes. migrations.md.
Guest: someone trying the app before logging in, with a pod kept in the browser. guest-mode.md.
Instance: one Solid Memo folder in a pod, with its own decks, reviews and preferences. A pod may hold several. data-model.md.
Receipt: a note in the digest that a document, at one version, conformed to the shapes, so it need not be checked again. data-model.md.
Release: one published version of a deck, frozen once published. deck-library.md.
Retired: a card, chapter or step marked owl:deprecated true. It is kept, with its history, but no longer studied.
Series: all the releases of one deck, which the library's index names. deck-library.md.
Studio (Solid Memo Studio): the second app, for managing decks in bulk and writing and publishing releases. studio.md.
Write fence: what keeps an instance read-only while it is being moved or copied, so nothing is written halfway. guest-mode.md.