Commercial Airplane taking off over the ocean

Glossary of Aviation Terms – Aeronautical Glossary Terms

Whether to satisfy a casual interest in aviation or address the need to learn about it for your profession, it’s understandable to have a tough time memorizing the formal definitions of aviation terms. The world of aviation practically has its own language. To master it, use a list of common, and not-so-common, terms compiled by Proponent as a study aid. By making time to read and practice this vocabulary regularly, a dedicated hobbyist or aspiring pilot can make steady progress toward their goals.


Absolute Altitude: The distance from the ground to the aircraft while it’s flying.

Adiabatic Lapse Rate: A mathematical formula measuring the rate of change in atmospheric temperature depending on decreases or increases in altitude in thermal equilibrium.

Adverse Yaw: The tendency of the aircraft’s nose to turn in the opposite direction of a turn.

Aeronautical Information Manual: An official document produced and distributed by the Federal Aviation Administration to instruct pilots in proper aircraft operation within the U.S. National Airspace System. Also known as AIM.

Aileron: Hinged surfaces at the trailing edges of an aircraft’s wings to help it stay balanced.

Air Defense Identification Zone: The airspace over land and water in which a civil aircraft’s location, identification, and control is monitored for the sake of national security. Also called ADIZ.

Air Speed Indicator: An instrument that uses miles per hour and/or knots to display the airspeed of an aircraft. Also known as ASI.

Air Traffic Control: A service that directs aircraft on the ground and within a specific airspace, in addition to advising aircraft outside their designated airspace, in order to avoid collisions. Also known as ATC. 

Airfoil: The cross-sectional shapes created by wings, rotos, turbines, and blades when the aircraft lifts.

Altimeter: An instrument in the cockpit that uses air pressure to calculate the aircraft’s altitude.

Angle of Attack: The angle created with an airfoil’s chord line and the direction of the air that passes through it.

Anhedral: The downward angle produced by a wing’s relation to the horizontal cross-sectional line of the wings.

Apron: A designated space at an airport at which an aircraft can park for fueling and loading.

Automatic Direction Finder: A radio navigator that automatically indicates an aircraft’s bearing to a radio station based on signals in the LF or MF bandwidth. Also called ADF.

Automatic Terminal Information Service: A pre-recorded compilation of information specific to aviation to help pilots navigate particular terminals. Also known as ATIS.

Aviation Alphabet: The practice of using unmistakable words to indicate the letters necessary to spell out another word in order to avoid confusion. For example, A is for alpha, so when spelling a word that needs the letter A, simply say, “Alpha.” Outside aviation, this is called the phonetic alphabet.

Base Leg: A flight path descending in the direction of an airport runway.

Bleed Air: Condensed hot air emitted by the engine and used to heat and de-ice the jet at high pressure.

Black Box: An electronic flight recorder that keeps track of the flight’s altitude, speed, and position, along with any discussions between the pilots.

Block time: The measurement of time between the plane’s departure from its gate and its arrival at the next.

Calibrated Airspeed: The airspeed when taking position and instrument inaccuracy into account.

Camber: The degree of convexity in an airfoil’s curve.

Cargo: Goods, products, and other items carried in an aircraft.

Ceiling: The altitude of the lowest cloud or similar material obscuring the view.

Ceiling and Visibility Unlimited: Describes optimal flying conditions, characterized by the ability to see ten miles out and ten thousand miles down. Also called CAVU.

Chord Line: The invisible line stretching between an airfoil’s foremost edge, or its leading edge, and its rear edge, or tailing edge.

Constant-Speed Propeller: A propeller built to automatically change the angles of its blades so that the engine has a steady RPM.

Course Deviation Indicator: An instrument that indicates when and by how much the aircraft is veering off-course. Also called CDI.

Crosswind: Wind blowing across the aircraft’s course.

Deadstick: Forcing the aircraft to land when the propeller and engine cease to function.

Distance Measuring Equipment: A device that calculates the distance between the aircraft and a ground station using radio navigation.

Distress: Urgent trouble on the aircraft that must be resolved immediately.

Downwash: Air pushed down by a wing or rotor blade, often as the aircraft ascends.

Downwind Leg: A flight course parallel to the runway but heading in the opposite direction.

Drag: A force moving opposite but parallel to the aircraft’s course.

Emergency Overrun: A clear area on the runway designed to prevent as much damage as possible to an aircraft if it cannot stop.

Empennage: Another word for an aircraft’s tail, consisting of a fin, rudder, and stabilizer.

Feathering: Minimizing drag by adjusting the pitch propellers to match the airflow.

Federal Aviation Authority: An organization authorized by the U.S. government to monitor and manage civil aviation.

Firewall: A fireproof bulkhead, or barrier, placed between the engine and other parts of the aircraft.

Fixed Base Operator: A private airport-based business that fuels, maintains, repairs, hangars, and parks aircrafts, in addition to training pilots and offering charter services. Also known as an FBO.

Flaperon: Control surfaces on an aircraft’s wings meant to let the pilot manage a roll or bank.

Flaps: Flat surfaces on an aircraft’s wings designed to alter the wings’ curves and allow the pilot to control lift and drag at low airspeeds.

Flare: Pulling the aircraft’s nose upward as it descends and prepares to land.

Fuselage: An aircraft’s main body.

Go-Around: The decision of a pilot or the air traffic control to have the aircraft circle around the runway and try again to land.

Gone Tech: An aircraft has a technical flaw that prevents it from flying.

Horizontal Stabilizer: A small lifting surface that helps the aircraft stay stable from the edge of the tail.

Hypoxia: The state of having too little oxygen. Symptoms include rapid breathing, dizziness, reduced heart rate, confusion, etc.

Instrument Flight Rules: A set of rules that allow pilots to plan for flying under diverse meteorological conditions. Also known as IFR.

Instrument Landing System: A system that uses radar to help an aircraft land safely, regardless of meteorological conditions. Also called ILS.

Jet: An aircraft with engines capable of flying at or above the speed of sound.

Knot: A unit of speed measured by a single nautical mile or 1.15 statute miles.

Landing Gear: The undercarriage of an aircraft, assisting in takeoff, taxiing, and landing, in addition to offering structural support.

Level Flight: Keeping the aircraft at a steady altitude.

Longitudinal Axis: An invisible line cutting horizontally across the center of gravity, used for orientation.

Mach: A ratio measuring airspeed against the speed of sound in the air through which the aircraft is flying.

Magnetic Compass: A device that indicates the aircraft’s directional orientation relative to the north and south poles.

Magnetic Deviation: Technological errors caused by the magnetism of aircraft instruments.

Mean Sea Level: The average height of sea level.

N Number: A U.S.-registered aircraft’s registration number.

Navaid: A shortened term for “navigational aid,” referring to any device or tool that helps the pilot navigate.

Oil Pressure Gauge: An instrument indicate the pressure of the engine’s lubricating oil. 

Operating Limitations: An aircraft’s maximum speed, pressure, weight, and capacity for holding passengers and crew members. 

Pitch: Movement on the aircraft’s lateral axis from wing to wing, affecting the front end’s ascent and descent.

Pilot in Command: The pilot put in charge of the aircraft’s security and operation from takeoff to landing.

Primary Flight Display: An electronic screen showing the aircraft’s airspeed, vertical speed, altitude, rate of turn, and other important information.

Quadraplane: An aircraft with at least four similarly-sized wings.

Radar Approach Control Facility: A terminal-based facility run by either the military or civil organizations to help aircraft that are landing, taking off, or flying through controlled airspace, using both radar and non-radar equipment. Also called RAPCON.

Registration Number: A government-issued number on the exterior of the aircraft for the purposes of identification.

Report Time: The time that the aircraft’s crew must arrive at the airport to prepare for the flight, usually anywhere from half an hour to an hour before the passengers are due to board.

Runway: A specified stretch of ground designed to accommodate takeoffs and landings.

Short Field: An unusually short runway that requires the pilot to land or take off quickly.

SQUAWK: A four-digit number for identifying an aircraft when a pilot communicates with ATC.

Stall: When the angle of attack is severe enough to prevent air from passing smoothly over the airfoil.

Threshold: A designated area of the runway on which the aircraft can land.

Throttle: A valve that manages the amount of fuel allowed in the engine.

Thrust: A force generated by the propeller to reduce drag and push the aircraft forward.

Torque: A force that causes a twist designed to create rotation.

True Airspeed: An aircraft’s airspeed after including temperature and altitude in the calculation.

True Altitude: An aircraft’s altitude from mean sea level.

Turbosuperchargers: A device that enhances the performance of a combustion engine with a device that uses turbine energy to increase pressure by compressing air.

Upwind Leg: A parallel flight path to that of the aircraft heading in the same direction as the runway.

Vertical Speed Indicator: An instrument that evaluates the shifts in atmospheric pressure to determine the rate of the aircraft’s ascent or descent. Also known as a VSI.

Very High Frequency Omnidirectional Range: A navigation system that lets the aircraft clarify its position and direction through short-range radio signals with beacons on the ground. Also called VOR.

Visual Flight Rules: A set of rules that govern aircraft operations when pilots are using visual references. Also called VFR.

Visual Meteorological Conditions: The weather conditions that allow VFR.

Wilco: A term indicating that you will follow the instructions given.

Wind Shear: A sudden shift in wind speed and direction.

YAW: The aircraft’s movement from side to side.

Yoke: The wheel that controls the aircraft’s movement, pitch, and altitude.

Zulu Time: A method for telling time used by all flight plans, characterized by the use of the 24-hour clock. Other common terms are Greenwich Mean Time (GMT), Universal Coordinated Time (UTC), and military time.


Although there are a lot of aviation terms to learn, it’s doable with time and effort. Make flashcards to study whenever a spare moment presents itself. Soon enough, every word from this list will come as naturally as your everyday conversational language. If you have any questions for Proponent we’re glad to help. You can contact us here.

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