FPV Quadcopter Acronyms, Terminology, Glossary

Here is a glossary of technical terms, abbreviations and acronyms often used in FPV, mini quad, quadcopter, racing drones and RC in general. Some jargon can be difficult to understand for beginners, hopefully this list of drone technical terms will help clear the confusion.

Let me know if there is any missing terms or abbreviations.

Acronyms Stands For Explanation
2.4GHz, 5.8GHz Hz = Hertz
GHz = GigaHertz
Frequencies used in RC and FPV.
1S, 2S, 3S, 4S, 5S, 6S… These numbers indicate how many cells in a LiPo battery. The higher the cell count, the higher the nominal voltage. See our LiPo battery tutorial
AC Alternating Current The type of electricity that comes from your wall socket. Uses Live and Neutral, as opposed to positive and negative (+ & -)
ACC Accelerometer A device that measures acceleration forces in a specific direction.
Acro Acrobatic It means multiple things, when referring to flight mode, it’s means “rate mode”; when referring to hardware, it’s more or less saying “free style” or “acrobatics”
Active Braking AKA “Damped Light”, it’s a feature in BLHeli that improves throttle responsiveness.
ADC Analogue to Digital Converter A type of circuit to convert analogue signal to digital signal; OpenTX has an “ADC Filter” option to reduce stick jitters
AH Altitude hold A flight mode that maintains height of the drone using a barometric sensor (BARO), or ultrasonic sensor
AIL Ailerons Also known as roll (It’s the letter “A” in channel map, TAER1234)
Air Mode FC firmware feature that keeps PID controller working even when throttle is at zero, what is air mode
AL Auto Levelling A flight mode that allows the copter to stay level. It uses “ACC” sensor
ALT Altitude The vertical distance you are from ground
Angle Mode A stabilized flight mode using both gyroscope and accelerometer sensors; See Self-level mode vs. Acro mode
AP Aerial Photography Using a multirotor to take aerial videos and photos.
APM Ardu Pilot Mega A type of flight controller board
Arducopter A type of flight controller software
ARTF Almost Ready to Fly An ARTF aircraft package usually includes everything you need to fly, only requiring simple assembly.
AUW All up weight The total weight of a copter including LiPo Battery and necessary parts in order to take off, and any other peripherals
AUX Auxiliary Channels Channels in addition to those used for the control sticks – for example, the switches, rotary controls and sliders. These can be used for changing flight modes & controlling peripherals
AWG American wire gauge An electrical wire size measurement, the larger the number, the smaller the wire. See Wire Gauage for Multirotors
Band There are a number of VTX frequencies which are split into bands, there are 8 channels per band. See 5.8Ghz frequency for FPV
BARO Barometric Altimeter It measures altitude by using barometric pressure
BEC Battery Eliminator Circuit A voltage regulator found in some PDB, ESC, FC and VTX. They are designed to provide constant voltage, e.g. 5V and 12V, for other RC equipment such as FPV camera and radio receiver
BF Betaflight Betaflight is a popular fc firmware for racing drones
BNF Bind and Fly Usually a BNF plane, helicopter, or quadcopter requires only a battery and radio transmitter to fly. Sometimes even the battery is included.
Bind The process of pairing radio transmitter and receiver when first setting them up to work together
BLDC Brushless Direct Current Motor Despite your quadcopter using a DC battery, BLDC motors are not to be confused with the brushless motors on a quad, which actually run on 3 Phase AC.
Bootloader Special code stored in non-volatile memory in a microprocessor that can interface with a PC to download a user’s program.
Brushed Motor A type of motor that is commonly used in small multirotors, they are generally powered by 1S batteries, and weaker than brushless motors
Brushless Motor A type of electrical motor that is commonly used in multirotors. They have a wide range of voltage input, more durable and powerful than brushed motors. How to choose mini quad motors


BuF Butterflight A fc firmware for racing drones
Buzzer A very loud speaker commonly used in drones, for the purpose of low voltage and lost model alarms
CC3D CopterControl 3D A type of flight controller
Cell LiPo battery consists of cells. Each cell has a nominal voltage of 3.7V. In order to obtain higher voltage, cells are connected in series. Reference to a “4 cell or ‘4S’ LiPo” is a 14.8v battery with 4 cells in series
CF – Carbon Fiber
– Cleanflight
It can mean 2 things in this hobby: carbon fibre, the material used in quadcopter frames; or Cleanflight, a flight controller firmware
Channel Video transmitters broadcast signals on a particular frequency, and this frequency is a channel, each VTX can support multiple channels; Channel can also refer to the controls on a radio transmitter
COG or CG Center of Gravity The average location of the weight of a copter. It’s important to make sure the COG of your copter is right in the middle (or close enough)
Crius A type of flight controller board
CW / CCW Clockwise / Counter-Clockwise Describing the rotational direction of motors or propellers
DC Direct Current DC is the type of electricity that comes from power source with Positive and Negative (+ and -), such as a battery. In DC circuitry Negative is often referred to as GND, Ground or common.
DD Direct Drive A type of prop designed to go straight on a motor shaft without a gear reduction.
DFU Device Firmware Update For some FC, firmware can be flashed by putting it in DFU mode
Diversity Receiver A multiple receiver FPV system picks the strongest signal from multiple video receivers and antennas to display the best picture
DOF Degree of Freedom It gives clues as to what’s on the “IMU”. For example 6DOF = 3 axis Gyroscope (gyro) + 3 axis acc; 9DOF = 3 axis Gyroscope + 3 axis Accelerometer + 3 axis Magnetometer; 10DOF = same as 9DOF and adds a Barometric Altimeter
DShot Digital Shot A type of ESC protocol, what is DShot
DSM / DSM2 / DSMX These are the proprietary technology of an RC equipment maker, Spectrum, and DSM stands for “Digital Spectrum Modulation”.
DSSS Direct-Sequence Spread Spectrum DSM uses Direct-Sequence Spread Spectrum (DSSS) modulation technique. As with other spread spectrum technologies, the transmitted signal takes up more bandwidth than the information signal that modulates the carrier or broadcast frequency. The name ‘spread spectrum’ comes from the fact that the carrier signals occur over the full bandwidth (spectrum) of a device’s transmitting frequency.
Dry Weight The weight of a multirotor including everything necessary to take off except the battery.
ELEV Elevator Also known as pitch, it’s the letter “E” in channel map, TAER1234)
EMI Electromagnetic  Interference EMI is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.
ESC Electronic Speed Control ESC is used to convert signals from a flight controller or radio receiver, and apply the right amount of power to the electric motors. ESC’s often include Battery Elimination Circuit (BEC), which provides power for the RC system and other onboard electronics.
FAA Federal Aviation Administration A United States Department of Transportation Agency, it has authority to regulate and oversee all aspects of civil aviation in the USA
Failsafe A mechanism to minimize the damage to the multirotor, and nearby objects in case of system failure; what is failsafe
FC Flight Controller Flight Controller is the brain of your multirotor.
FET Field-effect transistor FET is a device which enables us to use one smaller electrical signal to control another bigger one.
Flow A word often used in the hobby to describe fast and smooth flying with style
FOV Field of View A measurement how much environment you can see through a camera lens. Usually measured in degrees.
FPV First Person View Utilizing an onboard FPV camera and wireless connection, to allow a pilot on the ground to see a live video stream from an RC aircraft, through an FPV goggle or monitor, while flying
FTDI Future Technology Devices International The name of the company that makes the electronic chip standard, to convert USB to serial communications. Available as a chip for boards that have a USB connector, or in a cable to connected to breakout pins.
FW Firmware Firmware is an application specific software designed for a specific piece of hardware / equipment.
GCS Ground Control Station Software used to monitor a Flight Controller Board. The OpenPilot GCS for example.
Gimbal It can mean two things: 1. a motorized camera stabilizer; 2. the entire stick control assembly within a radio transmitter
GIT A version control system for software developers.
GPS Global Positioning System Used to track movement or hold position at pre-defined coordinates
GND Ground Ground or Negative of a DC electrical circuit
Ground Effect Air turbulence from propellers bouncing off the ground when the copter is hovering at really low altitude
GYRO Gyroscope Provides the angular velocity around 3 axes of space in degrees. Assists with keeping a quadcopter level and facing the same direction.
HEXA Hexacopter A type of multicopter, that has 6 motors, no servos, all motors on same level.
HK Hobbyking One of the biggest RC Vendors in the world with warehouses in EU, US, AU, RU and China.
Horizon Mode This is a stabilized flight mode, similar to Angle mode, but it allows the pilot to do roll and flip.
I2C Inter-Integrated Circuit A serial bus that allows multiple low speed peripherals, such as sensors, to be connected to a microprocessor.
IMU Inertial Measurement Unit A Break Out Board containing sensors that reads and sends data to the flight controller
IntoFPV One of the most popular forum for FPV Multirotor
Jello Undesirable high frequency vibration in flight footage
JST A type of battery connector for lower power micro drones
JST-SH A type of small connector for lower current applications, such as signals
Kalman Filter The algorithm used in Multicopter Flight controllers. It is primarily used to combine accelerometer and gyro data to provide an accurate description of aircraft attitude and movement in real time.
KK Kaptein Kuk Multicopter controller by Rolf Bakke
LC FILTER L = Inductor
C = Capacitor
An LC filter is a circuit that reduces unwanted frequencies (noise) from a power supply. A video feed needs stable power to operate optimally and an LC filter smooths the input power.
LED Light Emitting Diode One of the most efficient forms of lighting.
LiPo Lithium Polymer Battery Aka LiPoly. It’s the most commonly used power source for the RC hobby these days because of its high energy storage density-to-weight and high discharge rate.
LOS Line of Sight When you are flying your aircraft by watching your aircraft directly, you are flying LOS. Another way of flying is FPV.
Locked in A positive description of a multirotor’s stable and on-rail flying performance
LPF Low-pass Filter A technique that filters out high frequency signal
mAh milli-amp per hour An unit that measures the capacity of a LiPo battery
MegaPirate a flight controller program software that copies Arducopter
Mode1 / Mode2 These are the different transmitter stick configurations: mode 1, throttle stick on the right; mode 2, throttle stick on the left (more widely used). See RC Transmitter Basics.
MTOW Maximum take-off weight
Multishot An ESC Protocol, what is multishot
MWC MultiWii Copter MultiWii is a general purpose software to control a multirotor RC model. It can use various sensors but was initially developed to support Nintendo Wii console gyroscopes and accelerometers
OCTO Octocopter A type of multicopter, that has 8 motors, no servos, all motors on same level.
Oneshot Oneshot125 A faster way of communication between FC and ESC.
Opto ESC Opto ESC is a common saying for ESC without BEC
OSD On Screen Display A piece of hardware that overlays flight data in text or graphical form over an existing live stream video.
P “Battery cells in parallel” For example, a LiPo battery of 4S2P, has two 4S batteries connected in parallel.
Payload What the drone can carry/lift, such as a camera, or package
PAL / NTSC These are video formats in FPV cameras and your video display.
PCB Printed Circuit Board Silicon board with copper traces and components soldered onto it. Most electronics in this hobby are built on PCB’s, such as FC, VTX, TX, RX….
PID Proportional Integral Derivative The three parameters that you can adjust to change the copter’s flight performance. In theory PID is a control loop that attempts to minimize the difference between a measured process value and its desired value by adjusting the control input of a process.
PNP Plug and Play A PNP quadcopter kit usually comes without the receiver, transmitter, battery and FPV Goggles.
PPM SUM (CPPM) Pulse Position Modulation A way of sending sequence of multiple signals down one signal wire
Prop Propeller Short for propeller
Punch Sudden burst of thrust
PWM Pulse Width Modulation The square-wave signals used in RC control to drive servos and speed controllers.
Quad Quadcopter Short for quadcopter, which is a type of multicopter that has 4 motors on the same level
Rate Rate changes how fast your copter rotates with the sticks, what is rate
Rate Mode A.K.A. Acro Mode, and Manual mode. It’s a flight mode that only uses the gyro sensor. See what is rate mode
RC Radio Control The foundation of our hobby, it’s also used to refer to the hobby as a whole, radio controlled cars, multirotor, planes boats and more.
RCG RCGroups One of the most popular RC forum
Revo Revolution The 3rd generation of OpenPilot Controllers
RF Radio Frequency” or “Raceflight” Radio control link. common frequency used in this hobby are 2.4gHz, 900mHz and 433mHz; Raceflight is a popular fc firmware for racing drones
RPM Revolutions Per Minute the number of times a motor shaft  rotates a full cycle in 60 seconds
RSSI Received Signal Strength Indication RSSI is a measurement of how good your radio signal is.
RTF Ready to Fly A multicopter that’s sold with everything you will need in order to fly right out of the box.
RTH Return to Home A GPS feature that when enabled, it returns the aircraft to the “home” position where it took off.
RTL Return To Launch Same as RTH.
RUD Rudder Also known as yaw, it’s the letter “R” in channel map, TAER1234)
RX Radio Receiver” or the “RX pin in a UART” A device that receives commands from our radio Transmitter, and sends them directly to the servos or to the Flight Controller; RX can also mean the receive pin in a UART
S Cell Count – “Cells connected in series” For example, a 4S LiPo is a LiPo battery with 4 cells connected in series, nominal voltage is 14.8V (4×3.7).
SA Smart Audio Smart Audio is a protocol for VTX Control
SBUS SBUS is a type of serial communication protocol used by Futaba and FrSky. It supports up to 16 channels using only one signal cable. See the different radio receiver protocols
SF Slow fly A type of propellers that are designed to go on a motor using a gear reduction to lower rotational speed
SimonK An ESC firmware designed for multirotors, but no longer updated and now obsolete
SMA and RP-SMA Sub-Miniature Version A – Reverse Polarity SMA Different Connectors for FPV gear.
TAER1234 A type of radio channel mapping. It means mapping throttle as channel 1, Aileron as channel 2, Elevator as channel 3, and Rudder as channel 4
Throttle Controls on your radio transmitter, it changes the speed of the motors, it’s the letter “T” in channel map, TAER1234)
Thrust The force generated by the propellers and motor, measured in grams
TOW Take off weight Similar to AUW
TRI Tricopter A type of multicopter that has 3 motors,  one servo for yaw, all motors on same level
TVL TV Line TVL (TV Lines) is basically a measure of how good the FPV camera resolution is. The number is based on how many alternating black and white lines can be displayed in its image horizontally.
TX Transmitter” or the “TX pin in a UART” A device that sends our commands to the Receiver, controlled by the pilot; TX can also mean the transmit pin in a UART
UART Universal Asynchronous Receiver/Transmitter Serial communication port. A piece of computer hardware that translates data between parallel and serial form.
UAV Unmanned Aerial Vehicle Aircraft without a human pilot onboard. Control is provided by an onboard computer, remote control or combination of both.
UBEC Universal Battery Elimination Circuit a DC voltage regulator
Vcc Vcc Positive power supply input
VRX Video Receiver A device that receives video signal from our video Transmitter, and display the live footage on our FPV goggle or screen.
V-tail A type of multicopter that has 4 motors, 2 tail motors form a V shape, has no servo
VTOL Vertical take off and landing
VTX Video Transmitter A device that sends video signal to  our video receiver, video captured from a on-board camera. How to choose VTX
WOT Wide Open Throttle 100% throttle
X8 A type of multicopter that has 8 motors and of a shape of X,  4 motors on top, 4 motors at bottom, no servo
The most common type of battery connector type for multirotors. The number indicates current rating and size.
Y4 A type of multicopter that has 4 motors, 2 tail motors one on top of the other, it looks like a tricopter but has no servo
Y6 A type of multicopter that has 6 motors and of a shape of Y,  3 motors on top, 3 motors at bottom, no servo
Yaw Flight term used to describe the rotation of a drone around it’s center axis. Controls which direction the quadcopter is facing.

Edit History

  • Feb 2015 – Post created
  • Apr 2018 – Updated list

27 thoughts on “FPV Quadcopter Acronyms, Terminology, Glossary

  1. Barry Moore

    I am new to Quads since first of year, still learning jargon. Last night 7hatguy said to turn ADC off on your Frsky radios in the new BetaFlight 4.0. What does ADC stand for? I don’t see it in Quad glossary here.

    Thanks in advance

    1. Oscar Post author

      OpenTX has an “ADC Filter” option to reduce stick jitters.
      Long press Enter button, and scroll over to “hardware” page. the option of at the very bottom.

  2. Jacob Felix

    I have one abbreviation that have not seen or heard of. Maybe one you could help with. “KG” abbreviated on flight board I salvaged off a old SJRC toy drone. Anyone? Anyone?

  3. David Schick

    Here’s another one I came across not in your list: DFU. I think it means Device Firmware Update, but not sure.


    Thanks for the great work on your site!

    1. Matt

      DFU… It’s easy that one, it obviously stands for ‘Don’t F**k UP!’

      Sorry, very puerile of me, but I just could not resist hehehe

  4. voodoo

    Missing a few important one. I know you have CF for Cleanflight which is all the rage these days. But what about the lesser known FW like Betaflight. :)

    BF – Betaflight
    BFC – Betaflight configurator
    RF – Raceflight
    RFC – RF configurator
    BUF – ButterFlight
    RX and TX – confusing but often also referred to UART RX and TX
    FKF – Fast Kalman Filter
    # eg. 3S, 4S etc?

  5. Nobody In Particular

    One of the best list’s i’ve seen, Thank you. Let’s make it better with A few more ACRONYMS If I may suggest.
    1. CW/CCW- ClockWise / Counter ClockWise rotation.

    2.Add to Diversity: To read
    Diversity Tracking- An FPV setup that uses a dual receiver system that picks between multiple
    antennas to display the best picture.

    3. FW- Firmware, software designed specifically for a piece of equipment.

    4. LED- Light Emitting Diode.

    5. Mode 1- Tx throttle position – stick on the right.
    6. Mode 2- Tx throttle position – stick on the left (the more widely used configuration).
    7. MTOW- Maximum Take Off Weight.
    8. (n)S count- Series on a LiPo battery represents the number of cells that are connected in
    series. For example, a 3S LiPo has 3 cells connected in series. Each cell generally has around
    4V, so a 3S would have around 12V.
    9. Pal / NTSC- Both are video formats.
    10. PNP- Plug and Play.
    11. Polarization- A subject related to FPV antennas.
    12.RTF- Ready To Fly. A multicopter that’s sold with a radio transmitter. It can be flown right out
    of the box.
    13. TOW- Take Off Weight.

    14. VTOL- Vertical take off and landing.

    14. XT-60- battery connector type.
    Hope these help,

  6. Claudio Costerni

    Hi Oscar,

    nice work here, it helps a lot, thanks.
    I have found a typo:

    SimonK A famous ESC firmware optomised for multirotors

  7. Edwin Brandt

    Quadcopter Acronyms – Terminology – Glossary – Vocabulary – Drone Multirotors RC
    Ground Effect :- The effect ( back Wash or impact induced ) on the flight characteristics of the crafts own Propellers on Air induced BOUNCE when hovering or at the Take-Off & Landing of Craft from surounding Solid Obstacles ( i.e. Ground , Walls etc. ) usualy seen as Dust Cloud .

    Ermmm yea i think thats what i mean , I saw it missing so im kinda being presumtuious

    1. robert

      I am in same position low blow. I’m so happy i finally found this info. It would have been expensive to learn by experimentation, which is what I had been doing.


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