Astronomy
- Brachial (adj.) – Relating to galactic arms.
- Coreward (adv.) – Pointing towards the galactic core.
- Interbrachial (adj.) – Between galactic arms.
- Panthalassic (adj.) – Ascribed to rocky worlds with >75% of their surfaces covered in a liquid.
- Rimward (adv.) – Pointing towards the galactic rim.
- Terrestrial (noun) – A world with a mostly rocky physical composition.
- Worldfall (noun) – The process of landing on a world or penetrating its atmosphere (variants: planetfall, moonfall).
- Worldside (adj., adv.) – On a world (variants: planetside, moonside).
Biology
- Alga (noun) – A small to mid-sized photoautotroph with no terrestrial ancestry.
- Fish (noun) – A liquid-dwelling, motile, macroscopic, and multicellular chemoheterotroph with a streamlined body and no prior instance of terrestrialization along its evolutionary line.
- Fauna (noun) – Multicellular, ancestrally motile chemoheterotrophs from a particular place or time.
- Plant (noun) – A macroscopic, multicellular photoautotroph ancestrally adapted to a permanent terrestrial existence.
- Tree (noun) – A plant with a tall, woody stem supporting photosynthetic organs farther up.
Society
- Astrocommunications (noun) – Communication over interstellar distances.
- Astropolis (noun) – A group of interstellar space settlements that is tightly connected and possesses great cultural, economic, and political value to its host country.
- Astropolitics (noun) – Either the relationship between astrography and politics or the relationship between civilizations that control outer space.
- Corporate-governmental complex (noun) – The close relationship between private corporations and governments, typically observed in late-stage capitalism.
- Exclusive economic zone (noun) – An outlying area of space whose natural resources are under the exclusive control of a government or similar territorial authority.
- Sapientology (noun) – The scientific study of sapient species, their behavior, and their societies.
- Sapients' rights (noun) – Moral principles or norms established as standard to the behavior of a sapient species.
- Spacer (adj., noun) – A person residing primarily in outer space.
- Space settlement (noun) – A physically contiguous habitat within outer space.
- Specilect (noun) – A language typically spoken by one or more sapient species.
- Starway (noun) – A transport route between two or more points in interstellar space.
- War of sustenance (noun) – An armed conflict fought over the scarcity of resources.
Technology
- Gripgun (noun) – A gun designed to be held with a single gripping appendage.