| Air Start | When a motor is ignited during flight |
| American Countdown | 10-9-8 Whoosh! (See 10-9-8) |
| Apogee | When a rocket is at its highest point during flight |
| Aquajet | A rocket powered by water and compressed air |
| Boost Glider | A Glider which is powered by a rocket motor |
| CATO | Catastrophe At Take Off! |
| CG | Centre of Pressure |
| CP | Centre of Gravity |
| Centre of Gravity | The point on the rocket where all gravitational forces are assumed to act |
| Centre of Pressure | The point on the rocket where all aerodynamic forces are assumed to act |
| CHAD Staging | CHeap And Dirty Staging - usually by taping a booster motor directly to an existing rocket |
| Cluster | When more than one motor is used simultaneously to propel the rocket |
| Composite | A motor with a non-black powder based propellant |
| Copperhead | Igniter used with Aerotech motors, which appears to have only one lead. It is actually made from two pieces of copper foil sandwiched together separated by an insulator. |
| Core Burner | A rocket motor which a hole running up the centre of the propellant |
| Crapperhead | Affectionate term for Copperhead |
| Delay | The time between the motor burning out, and the Ejection Charge firing |
| Ejection Charge | Small Black Powder charge used to deploy a Recovery Device |
| End Burner | A rocket motor which has a cylindrical propellant grain and burns from one end |
| High Power Rocketry | Generally larger rockets powered by Composite Propellant (ie most things larger then Estes |
| HPR | High Power Rocketry |
| HPR Magazine | Magazine of the Tripoli Rocketry Association (Also available in the UK) |
| Hybrid | A rocket with a Solid Fuel, but a Liquid Oxidiser |
| Igniter | An electrical device used to ignite a rocket motor safely |
| Launch Controller | Device used to set off the igniter (and therefore launch the rocket) |
| Launch Rod | A rod which guides the rocket at launch until it reaches a speed at which it becomes aerodynamically stable |
| Launch Lug | Things attached to the side of the rocket, which run over the Launch Rod |
| Lawn Dart | Affectionate term for a rocket which fails to deploy its Recovery Device, and plummets into the ground nose first |
| Model Rocket | Generally a smaller rocket which uses black-powder based rocket motors |
| Multistage | A rocket which uses more than one rocket motor, with subsequent motors igniting when the previous ones have burned out |
| NAR | National Association of Rocketry (US Organisation) |
| Piston | Some larger rockets use a "piston" which pushes the Recovery Device out |
| Phenolic | Reinforced resin often used for making body tubes and fins for High Power Rockets |
| Positive Motor Retention | Technique used to ensure the rocket motor is not ejected when the Ejection Charge fires. |
| Quick Match | Fast burning fuse, ignited electrically, that is very useful for igniting Clusters |
| Range Safety Officer | Person who enforces the rules, to ensure the safety of all participants and spectators |
| Recovery Device | Usually a parachute or a streamer used to slow the descent of the rocket, both for safety and to help protect the rocket when it lands |
| Reload | Kit containing propellant, ejection charge etc. to be used with reusable rocket motors |
| RSO | Range Safety Officer |
| Safety Code | A set of common-sense rules which should be followed when building and flying rockets |
| Shock Cord | Overpriced knicker elastic used to relieve some stresses involved when the ejection charge fires. High Power Rockets use something more substantial though! |
| Streamer | A long ribbon of paper or plastic used as a Recovery Device |
| TRA | Tripoli Rocketry Association |
| Tripoli Rocketry Assocoiation | US High Power Rocketry Association |
| Tumble Recovery | A method of recovery for very lightweight rockets and booster stages, whereby the rocket tumbles safely to the ground |
| UKRA | United Kingdom Rocketry Association |
| Wadding | Flame-proof tissue used to protect Recovery Devices from the Ejection Charge |
| Water Rocket | A rocket powered by water and compressed air. Also known as an Aquajet |
| Waverider | Hypersonic glider which uses an attached and a detached aerodynamic shockwave to create lift |
| 10-9-8 | Running joke, when a particular (American) high power rocket was accidentally launched (very) prematurely during the countdown at the 1996 International Rocket Weekend in Scotland. The rocket and the launcher shall remain anonymous, but most UK HPR guys witnessed the launch! |
| 10-9-8 | Name adopted for the UKRA newsletter. Named after the American Countdown |