Magento 2 Glossary

Access Control List: Magento's admin permission system. Resources are defined in acl.xml, and each admin controller or web API route names the resource it requires.

A PHP class that prepares data for a template to display. Layout XML pairs each block with a template, which accesses it through the $block variable.

A head tag that names the preferred URL for content reachable at several addresses. Magento 2 outputs it for products and categories once the setting is enabled in the admin.

A class that loads a set of records and lets you add filters, sorting and limits before the query runs. The query only executes when the data is actually needed (lazy loading).

Magento 2's scheduler for recurring tasks such as indexer updates, emails and sitemap generation. Jobs are declared in crontab.xml and need a server cron entry that runs bin/magento cron:run.

A class that applies a one-time data change, such as adding an attribute or default records. Magento records applied patches in the patch_list table so they never run twice.

Defining database tables in etc/db_schema.xml instead of install scripts. You describe the table structure you want, and setup:upgrade applies the difference.

A design pattern in which a class receives the objects it depends on through its constructor instead of creating them. In Magento 2 the Object Manager supplies them based on di.xml configuration.

The mode Magento runs in: default, developer or production. Production is the fastest and serves pre-generated static and compiled files; switch with bin/magento deploy:mode:set.

A module's dependency injection configuration. It declares preferences, plugins, virtual types and constructor arguments, and lives in etc/ or an area folder such as etc/frontend/.

Entity-Attribute-Value: a storage model that keeps each attribute value in its own row instead of one column per attribute. Magento 2 uses it for products, categories and customers so attributes can be added without changing table structure.

An auto-generated class that creates new instances of a given type, such as ProductFactory::create(). Use it when you need a fresh object each time rather than the shared instance injected by default.

A cache that stores whole rendered pages as HTML so repeat requests are served without Magento rebuilding them. Adobe recommends Varnish rather than the built-in cache in production.

A class implementing ResolverInterface that returns the data for a GraphQL field or query. It is bound in schema.graphqls with the @resolver directive.

A process that transforms scattered data such as prices, stock and EAV attributes into tables built for fast storefront reads. Indexers run in Update on Save or Update by Schedule mode.

A JavaScript data-binding library that keeps the interface in sync with data. Magento 2 uses it in the checkout, the mini cart and UI components.

An identifier that selects which layout files apply to a page; it matches the file name, such as catalog_product_view for product pages or default for every page.

XML files that define page structure: which blocks and containers appear, where, and in what order. Magento merges layout files from all modules and the active theme.

Magento's framework for sending messages from a publisher to a consumer that processes them in the background. It works with RabbitMQ (AMQP) or a MySQL-based adapter and is configured in XML files under etc/.

The basic unit of functionality in Magento 2: a directory of code, configuration and view files, registered by registration.php and declared in etc/module.xml, that can be enabled or disabled on its own.

Multi-Source Inventory: Magento 2's inventory system for multiple stock sources such as warehouses and stores, which calculates salable quantity using stocks and reservations.

Magento's materialized view mechanism: database triggers record changed rows in changelog tables so indexers in Update by Schedule mode process only those rows via cron.

The Magento 2 component that creates objects and injects their dependencies. Module code should not call it directly; request dependencies through the constructor instead.

A class that runs when a specific event is dispatched, such as a product being saved or an order being placed. Observers are registered in events.xml against an event name, following a publish/subscribe pattern.

A class that changes the behaviour of a public method of another class without editing it, using before, after or around methods. Plugins are registered in di.xml, and several can apply to the same method.

A di.xml setting that tells Magento to use a specific class in place of an interface or another class. It replaces the whole implementation, and if several modules declare one for the same type only one takes effect.

An auto-generated class that defers creating the real object until it is first used. It is configured in di.xml so an expensive dependency is only created when actually needed.

Magento's working cart: it holds items, addresses, shipping and payment methods and totals during checkout, and is converted into an order when the customer places it.

An in-memory data store. Magento 2 can use it as the cache backend and for session storage, reducing load on the database and file system.

A class that provides save, load, delete and search operations for one entity type (save, getById, getList, delete), hiding the resource model and collection behind a stable interface.

A JavaScript module loader that manages dependencies between scripts. Magento 2 configures it through requirejs-config.js and initialises modules from templates with x-magento-init or data-mage-init.

A set of PHP interfaces (data interfaces plus repository or service interfaces) that define a module's public API. Other modules and the REST API depend on them instead of internal details.

The setup:static-content:deploy command, which publishes CSS, JavaScript, images and translation files to pub/static for each theme and locale. In production it must run after frontend changes.

The lowest level of the store hierarchy, usually one per language. It controls translations and store-view-scoped values such as product names and meta data.

Interface components declared in XML and driven by JavaScript, such as admin grids, admin forms and checkout steps. They receive their data from a data provider.

A record in the url_rewrite table that maps a readable URL such as /iphone-15.html to an internal path, optionally as a 301 or 302 redirect. Created automatically for products and categories or manually in the admin.

An HTTP reverse proxy that serves cached pages before requests reach PHP. Magento can generate its VCL configuration, and Adobe recommends it for full page caching in production.

A file that maps a URL and HTTP method to a service contract method and names the required permission, letting Magento expose a REST endpoint without a controller.

The top level of the store hierarchy below Global. It groups stores that share payment and shipping settings and can separate customer accounts and prices when configured to.