Terminology

A

AI: Artificial Intelligence, synthetically-created computer intelligences. May or may not be sapient.
Astral Plane: Any alternate dimension or universe accessed through an astral rift.
Astral Rift: A tear in spacetime that leads to an astral plane.

B

Binary System: A star system with two main stars.
Black Hole: A point in spacetime with gravity so strong that not even light can escape.

C

Collective Consciousness: See "Gestalt Consciousness".
CoM: Commonwealth of Man.
Cosmic Storm: Multidimensional storms that can inflict severe damage on spacecraft and colonies across many lightyears.
Cybernetics: Mechanical components integrated into a biological being.
Cycle: A concept referring to the cyclical rise and fall of civilisations throughout galactic history.

D

Deep Space: The space between star systems.
Droid: Advanced robot that lacks the capacity for sentience.
Dyson Sphere: A shell containing a star for the purpose of extracting all of its energy. Far beyond current technology.
Dyson Swarm: A series of energy-collection satellites stationed around a star to efficiently collect its energy.

E

Ecumenopolis: A planet entirely covered by a city.
Empire: Shorthand for a star nation or interstellar polity. Alternatively, a hereditary monarchical form of government with an Emperor as its head.
Enclave: Independent organisations that (for the most part) predate the current galactic cycle. They live and work in large space stations within the territory of larger empires.

F

Fallen Empire: Ancient, vastly powerful empires that have become stagnant and reclusive.
FTL: Faster-than-light speed, typically refers to hyper drives or subspace communications.

G

Galactic Community: An international organisation that passes binding laws on its member states and helps resolve disputes.
Galactic Council: The most powerful members of the Galactic Community, elected to protect the interests of its members using their additional legal powers.
Galactic Senate: The lawmaking body of the Galactic Community.
Gateway: Ancient megastructures located outside of major gravity wells that allow ships to near-instantly move to any other active gateway in the galaxy.
Gestalt Consciousness: Any being comprised of a single collective consciousness, such as a hive mind or machine intelligence.
Gigastructure: Colloquial term for hypothetical artificial structures even larger than ring worlds and dyson spheres.

H

Habitat: Spaceborne artificial structures capable of housing millions or billions of inhabitants. Comprised of a main habitat administration centre and many smaller orbitals.
Hive Mind: An organic gestalt consciousness.
Hydrocarbon: Combustible organic compounds such as crude oil, natural gas, and coal.
Hyper Drive: A method of faster-than-light travel that propels ships between stars at superluminal speeds through the hyperlane network.
Hyperlane: Strands of hyperspace that join stars and other significant gravitational bodies together. They can be breached by hyper drive-equipped ships to move at FTL speeds.
Hyperspace: A dimension of subspace that allows ships to move easily through it.

I

J

Jump: Usually in the context of a ship; engaging an FTL drive and transitioning from realspace to hyperspace or subspace.

K

Kilostructure: Colloquial term for 'small' megastructures such as orbital rings and dyson swarms.

L

L-Cluster: A satellite cluster of the galaxy not connected to the hyperlane network.
L-Gates: Mysterious ancient gateways constructed near black holes. They appear to have been built by nanites, and connect to the distant L-Cluster.

M

Machine Intelligence: An artificially created, networked gestalt intelligence.
Marauder: Spacefaring societies that raid and demand tribute from anyone weak and close enough.
Megacorporation: Corporations that have supplanted the role of a state; alternatively refers to any large corporation.
Megastructure: Gigantic artifical structures, typically located in space.
MSI: Minamar Specialized Industries.

N

Nanite: Microscopic nanomachines that can perform a variety of tasks when programmed.
Neutron Star: An extremely small and dense kind of star formed from the remains of a supernova.

O

OCS: Orbis Customer Synergies.
Orbital: A smaller living and working station that houses inhabitants of a greater habitat complex.

P

Planetside: Referring to being on a planetary body .
Positronic Matrix: An advanced type of computer system that replicates organic brains. Considered by some to be sentient.
Pre-FTL: Societies that have yet to discover FTL travel. Most are unaware of alien life.
Primitive: Derogatory term referring to pre-FTL species.
Psion: Any individual with psionic abilities.
Psionics: Psychic powers possessed by some individuals and species. They draw power from the Shroud to exert their will on realspace.
Pulsar: A type of magnetised neutron star that emits a beam of radiation at extremely precise intervals, allowing for the precise measurement of time.

Q

R

Realspace: The dimension of spacetime that you, the reader, currently reside in.
Relic World: A planet covered entirely by a city but fallen to ruin.
Repulsor: Anti-gravity technology that allows vehicles, buildings, and even individuals to hover a short distance above the ground, or at least slow their descent.
Ring World: An artifical ring that spans an entire orbit around a star. Far beyond current technology.

S

Sapient: Possessing higher intelligence, wisdom, and self-awareness (adjective a being possessing sapience (noun).
Ship: Any spacefaring craft. Rarely refers to nautical planetbound craft.
Shroud: A higher dimension or plane of existence that can only be accessed by those with psionic power.
Spacer: An individual who primarily lives or works in space, such as a starship pilot or engineer.
Stagnant Ascendancy: See Fallen Empire.
Strike Craft: Small, one to four person armed spacecraft that operate from a mothership like a carrier or station. Most can also fly in-atmosphere.
Subspace: A dimension of spacetime that underpins realspace. Used for FTL travel and communication.
Superluminal: Faster-than-light.
Synthetic: Advanced robots that can mount positronic matrices.
System: A star system, which includes any stars and their orbiting planets.

T

Technocracy: A form of government ruled by scientists and other experts, instead of politicians.
Tiyanki: Docile space fauna. Sometimes called "space cows".
Tomb World: A planet rendered near-uninhabitable by nuclear bombardment or extreme pollution.
Trinary System: A star system with three stars.

U

UNE: United Nations of Earth.

V

Void: Space or vacuum.
Voidcraft: Spacecraft.

W

World: Planet or moon.

X

Xeno: Generally accepted term for a species foreign to a given society (e.g. a Roc is a xeno in the United Nations of Earth).

Y

Z