Raspberry Pi documentation glossary

A/mA - Ampere/milliampere, the base unit of electrical current.
API - Application Programming Interface, a set of subroutine definitions, communication protocols, and tools used for building software.
Arm - A series of instruction-set architectures and processor microarchitectures, mostly developed by Arm Holdings based in Cambridge, UK.
Armv6 - The instruction set architecture used on the first Raspberry Pi (Pi 1) and the Pi Zero range.
Armv7 - The instruction set architecture used on the Raspberry Pi 2 range.
Armv8 - The instruction set architecture used on the Raspberry Pi 3 range; very similar to Armv7 in 32-bit mode.
balenaEtcher - A graphical tool for programming SD cards ready for use on our devices; available for Linux, Windows, and Mac. Now superceded by Raspberry Pi's own imaging tool, which can be downloaded here.
Bare metal - Programming the Raspberry Pi without using an operating system.
BCM2835 - The SoC used on the Raspberry Pi 1, Compute Module 1, and Raspberry Pi Zero range; see our official documentation.
BCM2836 - The SoC used on the original Raspberry Pi 2; see our official documentation.
BCM2837 - The SoC used on the Raspberry Pi 3, Compute Module 3, and Raspberry Pi 2 version 1.2; see our official documentation.
BCM2711 - The SoC used on the Raspberry Pi 4B; see our official documentation.
BLE/BTLE - Bluetooth Low Energy, a low-power version of the Bluetooth wireless communications protocol.
BT - Bluetooth, a short-range, low-bandwidth, wireless communication protocol often used for mobile devices.
CODEC - Coder/Decoder, hardware or software blocks that encode and/or decode video or audio data.
Compute Module - A Pi variant aimed at commercial customers; uses a different form factor, facilitating use inside other products.
config.txt - A file located on the boot partition of a Raspberry Pi's SD card that is parsed at boot time in order to enable, disable, and manage operating system features which cannot be changed after booting; see our official documentation.
CSI - Camera Serial Interface, a hardware interface for connecting cameras to SoCs.
DHCP - Dynamic Host Configuration Protocol, a network management protocol which dynamically assigns an IP address and other network configuration parameters to each device on a network.
DPI - Parallel Display Interface, an up to 24-bit parallel RGB interface via the Raspberry Pi's GPIO pins.
DSI - Display Serial Interface, a hardware interface for connecting LCD panels.
Device Tree (DT) - A data structure for defining hardware.
Device Tree source (DTS) - A human-readable source file to be compiled into a DTB.
Device Tree blob (DTB) - A binary file containing a Device Tree; the result of compiling DTS files.
dt-blob.bin - A binary file containing initial GPIO configuration that is read by the firmware at boot time; despite the name, this is not Device Tree blob (although it is compiled by the Device Tree tools).
DVI - Digital Visual Interface, a video interface for connecting a source device to a monitor or display; electrically compatible with HDMI, so a simple adapter can convert from one to the other (excluding audio, which DVI does not support).
Etcher - See balenaEtcher.
FAQ - Frequently Asked Questions! See our FAQ.
Firmware - Software that runs on a particular hardware device, for example a wireless chip or dongle; distinct from the usual software running on the Raspberry Pi in that it is usually a fixed binary blob of data that is loaded on to the device at startup; on the Raspberry Pi, the VC4 GPU requires firmware to be loaded to it at startup in order boot up and run the entire system.
GNU - The GNU Project is a free software mass collaboration project, which has produced huge amounts of software that is used on the Raspberry Pi, including Linux itself.
GPIO - General Purpose Input/Output, the programmable pins on the Raspberry Pi.
GPU - Graphical Processing Unit, a hardware device for handling graphical (and related) tasks at high speed; on the Raspberry Pi range up to the Pi 3B+, this is called the VideoCore4 (VC4), and is built into the SoC. On the Pi 4, a newer and faster version called VideoCore6 (VC6) is used.
HAT - Hardware Attached on Top, a specification for designing devices to attach to the Raspberry Pi; see the launch announcement.
HDMI - High-Definition Multimedia Interface, a standard interface for transmitting uncompressed video and compressed or uncompressed audio data from a source device to a display device.
HDCP - High-bandwidth Digital Content Protection, an optional encryption mechanism used for HDMI or DVI transmission.
Headless - A headless Raspberry Pi is one that does not have a display device, keyboard or mouse plugged in. Access is usually via a network connection, using a remote access protocol like SSH or VNC.
HVS - Hardware Video Scaler, a hardware block in the VC4 or VC6 GPU on all Raspberry Pi models that is used for manipulating and displaying bitmaps.
I²C/I2C/IIC - Inter-Integrated Circuit (pronounced I-squared-C), an electrical protocol used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication.
I²S - Inter-Integrated Circuit Sound, an electrical serial bus interface standard used for connecting digital audio devices together.
ISP - Imaging System Pipeline, a set of hardware (and sometimes software) stages that processes images from a camera into a high-quality result; the Raspberry Pi has a built-in hardware ISP that processes images captured from a camera attached to the CSI port.
ISP - Internet service provider.
LAN - Local Area Network, an Ethernet- or wireless-based communication network in a localised area, for example a house or office.
LED - Light-Emitting Diode, a semiconductor device that produces light using electricity.
Linux - The main operating system used on the Raspberry Pi; the particular customised distribution for the Raspberry Pi range is called Raspberry Pi OS; third parties have also produced their own distributions.
MSD - Mass Storage Device (amongst other things), such as an SD card or hard disk drive.
MQTT - MQTT stands for MQ Telemetry Transport, a lightweight and simple machine-to-machine protocol often used for IoT devices; see the MQTT website.
NAND - A NAND gate is a logic gate, specifically an inverted AND gate; can also refer to a type of flash memory that uses NAND logic.
NOOBS - New Out of Box software, easy OS system image installation for the Raspberry Pi range; note: NOOBS is no longer developed by the Raspberry Pi team, see PINN instead.
OTP - One-Time Programmable, a type of memory that can only be programmed once, and retains the programmed data after power off; used for serial numbers etc.
Overlay - A boot-time or run-time patch to a Device Tree allowing a degree of configuration by the user; see our official documentation for more details, or run dtoverlay -a in a terminal window for a list of available overlays.
Pink Pony/Unicorn - A feature request for a future Raspberry Pi model that is unlikely to happen.
PINN - A third-party development of the NOOBS system, often a better option than the official NOOBS.
PoE - Power over Ethernet, a mechanism to power a device through its Ethernet connection; we produce a PoE HAT for the Raspberry Pi 3 Model B+ and Raspberry Pi 4 Model B.
Polyfuse - A self-resetting electrical fuse used on some Pi models to protect against over-current; can take hours or even days to reset.
raspi-config - A command line tool for configuring Raspberry Pi OS's operating system features; see our official documentation.
Raspberry Pi Imager - The official graphical tool for downloading and installing operating system images to an SD card. Download it here.
Raspbian - An armhf build of the Debian source repositories.
Raspberry Pi OS (32bit) - A distribution of the Raspbian repositories targeted at the entire Raspberry Pi range.
Raspberry Pi OS (64bit) - A distribution of the Debian repositories targeted at the Pi 3 and Pi 4 models.
Raspberry Pi Configuration Tool (rcgui) - A graphical equivalent of raspi-config.
Raspberry Pi Desktop - A version of the LXDE desktop environment, specifically tailored to the Raspberry Pi (used to be called PIXEL).
raspivid, raspistill, raspiyuv, raspividyuv - A set of applications to run the Raspberry Pi Camera Module in various modes; see our official documentation.
RPF - Raspberry Pi Foundation, the original, UK-registered educational charity (1129409) that launched the Raspberry Pi.
RPT/RPF(T) - Raspberry Pi Trading, a wholely owned commercial subsidiary of the RPF which designs and develops all Raspberry Pi products, including magazines; all profits from the RPT go to the RPF for use in their educational programmes.
rpi-update - A program you can run on a Raspberry Pi to download the very latest test firmware and Linux kernel; there is no guarantee that the latest version will work correctly, so you should only run rpi-update if recommended by a Raspberry Pi engineer.
SoC - System on a Chip, an integrated circuit that comprises all components of a computer.
SPI - Serial Peripheral Interface bus, a synchronous serial communication interface specification used for short distance communication.
SSH - Secure Shell, a cryptographic network protocol for operating network services securely over an unsecured network; see our official documentation or the Wikipedia article on SSH.
TLA - Three-letter abbreviation, almost the entire reason for this glossary.
TLS - Transport Layer Security, a cryptographic protocol used to supply security over a computer network, often used to secure other protocols such as MQTT.
TP1/TP2 - Test points.
UART - Universal Asynchronous Receiver-Transmitter, a protocol for asynchronous serial communication in which the data format and transmission speeds are configurable.
USB - Universal Serial Bus, the main Raspberry Pi models have four USB sockets for connecting USB devices, for example mice or keyboards.
VC4, VC6 - The VideoCore4 or VideoCore6 GPU used on the Raspberry Pi; contains a large number of hardware blocks that handle graphics, cameras, display, CODECs, etc.
VNC - A graphical desktop sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer; see our official documentation.
Volt (V) - SI-derived unit for electrical potential difference.
vcgencmd - A Raspberry Pi-specific tool for communicating with the VideoCore GPU.
Watt - A measure of power often used when specifying power supplies.