The Aviation Industry has its own language and set of definitions. Here is an excerpt of it:

ABSOLUTE ALTITUDE   Measurable height of an aircraft above the actual terrain.
ABSOLUTE CEILING   The maximum altitude above sea level at which an aircraft can maintain level flight under Standard Air conditions.
AGL (Above Ground Level)   Altitude expressed as feet above terrain or airport elevation (see MSL).
AILERONS   An aircraft control surface hinged to the rear, outer section of each wing for banking (“tilting”) the aircraft.
AIRCRAFT MANAGEMENT   Comprehensive services provided by a management company for an aircraft owner. Details vary.
AIRFOIL   The shape of any flying surface, but principally a wing, as seen in side-view (cross section).
ALTIMETER   A highly sensitive barometer that shows an aircraft’s altitude above mean sea level by measuring atmospheric pressure.
ANGLE OF ATTACK   The angle between the airfoil’s chord line and the direction in which the aircraft is currently moving.
AOG (Aircraft on Ground)   Aircraft unfit to fly, in need of repair. Owner's worst nightmare
APPROACH (DEPARTURE) CONTROL   Radar-based air traffic control, usually at an airport tower, providing traffic separation up to 40 miles.
APRON   Hard-surfaced or paved area around a hangar. Also “Ramp.”
ATC (Air Traffic Control)   Service providing separation services to participating airborne traffic and clearances to land, take off or taxi at airports.
AVIONICS   The electronic control systems airplanes use for flight such as communications, autopilots, and navigation.
BLOCK RATES   Pre-paid hours for air charter at a contracted price.
CARBON OFFSET   monetary contributions to renewable energy research and production projects to “offset” carbon emissions of an airplane.
CHARTER   The “renting” of an aircraft with crew for a personal, business, or cargo flight from one point to another.
CHARTER CARD   Pre-paid air charter plan, either for a block of charter hours at a pre-defined fee, or a set debit balance in dollars.
CLASS I NAVIGATION   Operation of aircraft under visual meteorological conditions (VFR) primarily based on “see and avoid” procedures.
CLASS II NAVIGATION   Any en route flight operation that is not Class I, i.e.instrument-based navigation (IFR).
CLEARANCE   Formal instructions from air traffic control authorizing a specific action (climb or descend, entry into controlled airspace).
CONTRAILS   Streaks of condensed water vapour created in the air by aircraft flying at high altitudes; aka vapour trails.
CONTROLLED AIRSPACE   An airspace of defined dimensions within which air traffic control service is provided.
CRUISE SPEED   The normal speed attained at altitude once the aircraft is no longer climbing and is en route.
CRUISING ALTITUDE   A level altitude maintained by an aircraft while in flight.
DEADHEAD   To fly the return leg of a trip without cargo or passengers.
DRAG   Resisting force exerted on an aircraft in its line of flight opposite in direction to its motion. Opposite of thrust.
DUTY TIME   That portion of the day when a crew member is on duty in any capacity (not just in the air), limited by regulations.
EFIS (Electronic Flight Information Systems)   Glass cockpit avionics that integrate all flight parameters into one optimized instrument.
ELEVATOR   An aircraft control surface hinged to both rear horizontal stabilizers, changing the aircraft pitch attitude nose-up or nose-down.
EMPTY LEG   Also known as “one-way availability.” Usually posted as available for travel between two airports during a certain time period.
FAA (Federal Aviation Administration)   The Department of Transportation's agency for aviation.
FBO (Fixed Base Operator)   A business operating an airport terminal for non-airline, general aviation aircraft.
FERRY FLIGHT   A flight for the purpose of returning an aircraft to base or delivering an aircraft from one location to another.
FLAPS   Hinged surfaces on the inboard rear of wings, deployed to increase wing curvature (and thus, lift).
FLIGHT PLAN   Filed by radio, telephone, computer, or in person with Flight Service Stations.
FLIGHT TIME   Portion of the trip actually spent in the air.
FRACTIONAL OWNERSHIP   The purchase of a “share” of an aircraft.
FUSELAGE   An aircraft’s main body structure housing the flight crew, passengers, and cargo.
GENERAL AVIATION   Part of civil aviation comprising all facets of aviation except scheduled air carriers.
GPS (Global Positioning System)   Satellite-based navigation system operated by Department of Defence.
GPWS (Ground Proximity Warning System)   System designed to alert pilots if their aircraft is in immediate danger of flying into the ground.
GROUND SPEED   Actual speed that an aircraft travels over the ground also called “shadow speed.”
HANGAR   An enclosed structure for housing aircraft. Originated with lake-based floating homes of the original German Zeppelin airships.
HEAVY JETS   See “Large-Cabin Jets.” .
HORSEPOWER   The motive energy required to raise 550 lbs. one foot in one second, friction disregarded.
HUD (head-Up Display)   A transparent display that presents data without requiring the user to look away from his or her usual viewpoint.
IATA CODE   International aviation code for international airports.
ICAO CODE   Civil aviation codes for airports.
IFR (Instrument Flight Rules)   Rules for flights into clouds and low visibility, by reference to cockpit instruments and radio navigation.
ILS (Instrument Landing System)   A precision instrument approach system permitting aircraft to land with low ceilings or poor visibility.
JOINT OWNERSHIP   Purchase or lease of an aircraft by a number of owners, often through a partnership or limited company.
KNOT (Nautical Mile per Hour)   Common measure of aircraft speed equalling 6,080 feet or about 1.15 miles (For mph, multiply knots by 1.15.)
KTAS   True airspeed, in knots.
LARGE-CABIN JETS   The largest size aircraft that doesn't require a major airport runway. Typical capacity 9-15 passengers.
LAYOVER   A night spent in the middle of the trip in a city other than home base for the aircraft and crew.
LEG   Describes one direction of travel between two points. Commonly used in referring to a planned itinerary.
LIGHT JETS   See “Small-Cabin Jets.”
MACH SPEED   A number representing the ratio of the speed of an airplane to the speed of sound in the surrounding air.
MAYDAY   An international distress signal to indicate an imminent and grave danger that requires assistance.
MID-CABIN JETS   Typical capacity 7-9 passengers.
MRO (Maintenance, Repair & Overhaul)   Company licensed to provided services for the upkeep and airworthiness of airplanes.
NAUTICAL MILE   Defined internationally as equivalent to 1,852 meters or 1.15 statute miles.
NDB (Non-Directional Beacon)   A radio transmitter at a known location, used as an aviation or marine navigational aid.
PAN PAN   International call signal for urgency, indicating uncertainty and usually followed by the nature of the alert.
PART 91   The parts of Federal Aviation Regulations on non-commercial operations covering corporate flight departments.
PART 121   The parts of Federal Aviation Regulations on scheduled airline operations, including the publication of a schedule.
PART 135   The parts of Federal Aviation Regulations on non-commercial operations covering charter carriers.
PART 145   Certificate allowing an organization to perform maintenance and alterations on U.S.-registered aircraft.
PATTERN   The path of aircraft traffic around an airfield, at an established height and direction.
PAYLOAD   Anything that an aircraft carries beyond what is required for its operation during flight.
POSITIONING   Ferrying aircraft for departure from other than originating airport.
RADAR   System that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects.
RAMP   The apron or open “tarmac” in front of an FBO or terminal facility. This space is busy, used for deplaning, parking of aircraft, etc.
ROLL   One of three axes in flight, specifying the action around a central point.
ROTATE   In flight, any aircraft will rotate about its centre of gravity, a point which is the average location of the mass of the aircraft.
RUDDER   Aircraft control surface attached to the rear of the vertical stabilizer (fin) of the aircraft tail. Forces the plane to veer left or right.
RUNWAY HEADING   Magnetic direction corresponding to the centre line of the runway.
SLATS   Small, aerodynamic surfaces on the leading edge of the wings of fixed aircraft which allow the wing to operate at a higher angle of attack.
SLIPSTREAM   The flow of air driven backward by a propeller or downward by a rotor.
SMALL-CABIN JETS   Typical capacity 5-8 passengers.
SQUAWK   A four-digit number that a pilot dials into his transponder to identify his aircraft to air traffic controllers.
STATUTE MILE   A unit of length equal to 5,280 feet.
SVS (Synthetic Vision System)   A technologies that use 3D to provide pilots with intuitive means of understanding their flying environment.
TAIL NUMBER   An airplane’s registration number.
TARMAC   A paved airport surface, especially a runway or an apron at a hangar.
TAXI TIME   Portion of the trip spent rolling between the gate, terminal, or ramp and runway.
THRUST   The forward force produced in reaction to the gases expelled rearward from a jet engine. Opposite of drag.
TRAILING EDGE   The rearmost edge of an airfoil.
TRANSPONDER   An airborne transmitter that responds to automated air traffic control interrogation with accurate position information.
TURBINE   Engine that uses compressed air to generate thrust to spin a metal shaft inside the motor, used in jet engines and turboprop aircraft.
TURBOPROP   An aircraft in which the propeller is driven by a jet-style turbine rather than a piston.
VERY LIGHT JETS (VLJ)   Small jet aircraft approved for single-pilot operation, maximum take-off weight of under 10,000 lb (4,540 kg).
VFR (Visual Flight Rules)   A defined set of FAA regulations covering operation of aircraft flying by visual reference to the horizon.
VOR (VHF Omnidirectional Range)   Ground-based radio navigation aid.
VORTICES   Regions of high velocity that develop at the tip of a wing as it flies through the air.
WIND SHEAR   Large changes in either wind speed or direction at different altitudes that can cause sudden gain or loss of airspeed.
WINGLET   A small, stabilizing, rudder-like addition to the tips of a wing to control or employ air movement, thereby increasing fuel economy.
YAW   One of the three axes in flight, specifying the side-to-side movement of an aircraft on its vertical axis.
YOKE   The control wheel of an aircraft, akin to an automobile steering wheel.