Weyr: A central location populated by many dragons and their riders.

weyr: Any place where a dragon lives.

Weyrwoman: The rider of the oldest queen dragon in a Weyr. This position is held from the time a dragon becomes the Senior Queen until either that dragon's death, or until the pair steps down.

weyrwoman: Another word for a goldrider.

Weyrleader: The rider whose dragon has mated with the senior queen in her latest mating Flight.

Weyrling: The rider of an immature dragon, or a dragonrider still in training. This term applies both to the rider and his/her dragon.

Impression: The moment when a dragon and rider form a telepathic bond. This bond lasts until one or the other dies. If the dragon dies, it is not uncommon for the rider to go mad. If the rider dies, the dragon will suicide by going Between.

Between: A non-space through which dragons and their riders pass while teleporting. To get anywhere on Pern, the duration of time spent Between should last no longer than 3-5 seconds.

Thread: A mycorrhizoid spore that falls from the Red Star when it passes close to Pern. Thread will devour any organic material it touches. Extreme cold, water, or fire will kill Thread.

Red Star: A rogue planet on an elliptical orbit around Rukbat. The Red Star passes through the Oort cloud and drags extraplanetary material behind it as it orbits. When the Red Star passes within proximity of Pern, it results in Threadfall.