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A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

For questions that require plausible (better than suspension-of-disbelief) answers based on Real World science that are not necessarily constrained to the known limits of Real World science. Contrast …
For questions that ask if a given concept is consistent, or being used consistently, in the context of the referenced world rules. Answers should say yes or no, with supporting info. This tag should n…
6178 questions
For questions about living things. Does not exclude aliens, but additional information is usually necessary (consider using "xenobiology" instead).
For questions about any large astronomical bodies classified as planets, and their effects on their systems.
For questions regarding the viability of a life-form design. These questions should focus on biologically plausible creatures.
For questions that have to do with magic, as opposed to science/technology. Remember to explain any limits.
For questions about the creation, use, and application of all types of technology.
For questions that allow fanciful, creative or imaginative solutions based on or rationalized by real world science, but not necessary limited by real world science. Entirely magical solutions must us…
For questions dealing with how sentient beings interact with each other in a community.
For questions regarding the physics relevant to fictitious worlds. General physics may be off-topic.
For questions related to the effects of certain circumstances, conditions, or locality changes on war. Related tags: [civil-war], [nuclear-war], [cold-war]
For questions about the long-term change of a specific species, type of creature, or trait, usually through the process of natural selection and reproduction. Ideal questions focus on traits, not enti…
For questions about existing weapons or designing new ones.
For questions related to outer space, stellar systems, stars and other astronomical phenomena.
For questions about humans as we know them or slightly changed, their physiology, psychology, politics, society and goals.
1383 questions
For questions related to the biology of extra-terrestrial organisms. This tag implies the use of the science-fiction tag. Use the science-based or hard-science tags to impose greater scientific restri…
1342 questions
For questions about the medieval era (500-1500AD o.e.) as a whole, regardless of the location.
For questions about a different and uncharacteristic species or object that has come to the world from another world. NOT for questions about extraterrestrials in their native environment.
1081 questions
REVIEW THE WIKI BEFORE USING THIS TAG! For questions that require unequivocal proof that answers are correct through the use of equations, empirical evidence, scientific papers, etc. Compare to: scien…
1003 questions
For questions regarding wealth, trade, or financial concepts.
975 questions
For questions about the process of traveling through space, including in orbit around a planet or moon. Consider also [spaceships]. See also the tag information (click "info") for more details on when…
968 questions
For questions about an environment or aspects of it such as geographical, atmospheric or climate.
943 questions
For questions involving implemented theory or technology for travelling through space. Consider also [space-travel]. See also the tag information (click "info") for more details on when this tag appli…
918 questions
For questions about specific changes in the characteristics of the weather in a location. You should also consider the tags [weather] and [seasons].
For questions that ask what might have happened if history had taken a different path.
832 questions
For questions about the gases which surround a planet or some other celestial body.
For questions about the characteristics and effects of natural features on a world.
802 questions
For questions dealing with events taking place after a catastrophic event.
799 questions
For questions dealing with the customary and artistic characteristics of a society.
769 questions
For questions regarding planets similar to Earth in most respects. This tag should be used when describing a planet that follows the rules of Earth with exceptions outlined in the question. Usually q…
For questions about animal life in general.
748 questions
For questions relating to peoples or sentient beings that are often found in the fantasy subgenre of fiction, such as elves, dwarves, etc. This can be about their physical characteristics, their socie…
741 questions
For questions pertaining to natural satellites, such as our own Moon.
725 questions
For questions about the universal accelerative force between all objects.
720 questions
For questions about the progress of a society's technological state.
716 questions
For questions about governance of the people, including methods, effects, and interactions with the people.
715 questions
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