Below are a number of resources to use in defining terms and concepts related to space exploration.

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• Planetary Glossary
• Solar System Terms
• Solar-Terrestrial Terms
• Comet Definitions
• Comet and Meteor shower glossary
• High-Energy Astrophysics Dictionary
• Spaceflight Terminology
• Glossary on Meteor Astronomy
• NASA Thesaurus
• Astronomy Unbound
• NASA NGST Glossary