Mobile & Apps glossary: terms explained simply

A

Android App Bundle (AAB) Android App Bundle · AAB

Google Play's publishing format that defers APK generation to the store, tailoring lightweight device-specific binaries for each user.

Intermediate

Android Room Persistence Library Room Persistence Library · SQLite ORM

An abstraction layer over SQLite provided by Android Jetpack, enabling compile-time checked database queries and seamless offline caching.

Intermediate

APK (Android Package Kit)

The install file format for Android apps; opening it on a phone installs the app without a store, but the source must be trustworthy.

Beginner

App Permissions

The permissions an app asks you for to access your phone's camera, microphone, contacts or location so it can do its job.

Beginner

App Store (App Marketplace) App Store (Marketplace)

A platform where apps are published, searched for and installed, such as Google Play, Apple's App Store and regional stores.

Beginner

App Tracking Transparency (ATT) App Tracking Transparency · ATT

Apple's privacy framework requiring explicit user opt-in consent before apps can track their activity across external apps and websites.

Intermediate

ASO (App Store Optimization)

Optimizing an app's store page (title, description, images and reviews) so it ranks better in search and earns more installs.

Intermediate

B

Bootloader

A small program that runs when a phone powers on and starts the operating system; whether it is locked or unlocked decides what software can be installed.

Advanced

C

CodePush Over-The-Air (OTA) Updates CodePush Live Over-the-Air Update

A cloud service enabling mobile developers to deploy instant JavaScript bundle updates directly to user devices, bypassing app store review cycles.

Intermediate

Cross-Platform App

An app built from one codebase for several operating systems, with tools such as Flutter or React Native, giving near-native look and speed.

Intermediate

Custom ROM

An unofficial version of Android built by a developer community that replaces the phone's original operating system, such as LineageOS.

Intermediate

D

Deep Link

A link that, instead of opening an app's first screen, takes the user straight to a specific place inside the app, such as a product page.

Intermediate

Developer Options

A hidden Android settings menu with advanced options for programmers, such as USB debugging, animation speed and layout overlays.

Beginner

E

Emulator

A program that simulates another device or operating system on a computer, for example an Android phone inside Windows for testing or gaming.

Intermediate

eSIM (Embedded SIM)

A built-in digital SIM on the phone's own chip, activated by scanning a code or installing a profile instead of inserting a physical card.

Beginner

F

Fast Charging

Higher-power charging technology that fills a phone battery in less time, using a compatible charger and cable and managing battery heat.

Beginner

Flashing Firmware (Flashing a Phone)

Rewriting the phone's system software to its storage with a ROM file, to fix a software problem or install another version of the operating system.

Intermediate

Flutter Cross-Platform Framework

Google's open-source UI software development kit for building natively compiled applications across mobile, web, and desktop from a single codebase.

Intermediate

H

Hermes JavaScript Engine

An open-source JavaScript engine optimized by Meta for running React Native apps with instant startup times and reduced memory footprints.

Advanced

Home Screen Widget

A small part of an app placed on the phone's home screen that shows useful information such as time, weather or notes without opening the app.

Beginner

Hybrid App

An app built with web technology (HTML, CSS and JavaScript) and wrapped in a native shell so it installs like a regular app.

Intermediate

I

IMEI (International Mobile Equipment Identity)

The unique 15-digit number of every phone, like the device's ID number, used for identification, registration and tracking a lost phone.

Beginner

In-App Purchase (IAP)

A purchase made inside the app itself, such as game coins, ad removal or a monthly subscription, handled through the store without leaving the app.

Beginner

J

Jailbreak (iOS)

Bypassing iOS security restrictions on an iPhone to install unofficial apps and tweaks; a high-risk step that weakens the device's protections.

Intermediate

Jetpack Compose Android UI Toolkit

Google's modern declarative UI toolkit for native Android development written completely in Kotlin, replacing legacy XML layouts.

Intermediate

M

Mini App

A lightweight program that runs inside a larger app, such as a messenger or super app, and is available to users without a separate install.

Intermediate

Mobile App (Application) Mobile Application

A program installed on a phone or tablet that performs a specific job, from messaging and banking to games and maps.

Beginner

Mobile Background WorkManager

The recommended solution for persistent, deferrable background work on Android that executes even if the app exits or device restarts.

Intermediate

Mobile Biometric Authentication API Biometrics

Hardware-backed operating system APIs (Face ID, Touch ID, Android BiometricPrompt) authorizing user actions via biometric verification.

Intermediate

Mobile Clean Architecture (MVVM / MVI) Mobile Clean Architecture · MVI/MVVM · MVVM/MVI

Design patterns enforcing unidirectional data flow and strict separation between UI presentation, business domain, and data storage layers.

Advanced

Mobile Deep Linking Mobile Deep Linking · Universal Links · DeepLink

A mobile routing protocol routing users directly to a specific in-app destination or product view via HTTP URLs instead of landing pages.

Intermediate

Mobile Device Registry (Phone Registration)

An official national system, used for example in Iran, where a phone's IMEI is registered so it can work on local SIM cards and be tracked or blocked if stolen.

Beginner

Mobile Push Notifications Mobile Push Notifications · APNs & FCM

Server-initiated alert messages delivered by Apple Push Notification service (APNs) and Firebase Cloud Messaging (FCM) to mobile devices.

Intermediate

N

Native App

An app written for one operating system, such as Android or iOS, with that system's official tools and language, giving the best speed and access.

Intermediate

NFC (Near-Field Communication)

A wireless technology with a range of a few centimeters; a phone or card is brought close to another device for payment, data exchange or unlocking.

Beginner

O

OTA Update (Over-the-Air) Over-the-Air Update

A system or app update downloaded and installed over the internet without connecting to a computer; the usual way phones update today.

Intermediate

P

ProGuard & R8 Android Code Optimizer ProGuard & R8 Code Shrinking · R8/ProGuard

Compiler tooling that strips dead code, optimizes bytecode, and obfuscates class names to protect IP and shrink mobile app binary size.

Advanced

Push Notification

A short message an app or site sends from a server to the user, shown on the phone's screen even when the app is closed.

Beginner

R

React Native Framework React Native Mobile Framework · RN

Meta's open-source framework enabling cross-platform mobile development using JavaScript, React paradigms, and true native UI widgets.

Intermediate

Recovery Mode

A special phone mode that opens before the operating system boots, used for a full reset, clearing the cache or installing an update.

Intermediate

Rooting

Gaining full administrator (root) access on an Android phone, allowing deep system changes but weakening the phone's warranty and security.

Intermediate

S

Sideloading

Installing an app from outside the official store, usually with an APK file; a way to reach apps outside the store that carries security risk.

Intermediate

SwiftUI Declarative Framework SwiftUI Declarative iOS UI

Apple's declarative framework for developing user interfaces across iOS, iPadOS, macOS, watchOS, and visionOS using Swift.

Intermediate