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 with an element that only has two dimensions: length and width. This tag is only relevant when describing something that is often not two-dimensional.
For questions about how a certain species or object can change to fit a new criteria of living or other.
For questions having to do with the appreciation of beauty, be it in living or artistic form.
For questions related to the production of certain types of food: plants, nuts and everything else that is edible and cultivated.
For questions about heavier-than-air artificial objects designed to fly through an atmosphere, including fixed-wing aircraft and helicopters. Not for flight-capable living creatures (use [avian]) or l…
For questions involving large flying objects that are lighter than air.
to be used when considering the geometry of the universe itself. It refers not to extraterrestrial species, but to geometries completely foreign to normal experience.
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.
for questions relating to radically changed Earth. This alternate Earth could be a post-apocalyptic Earth, or Earth with major changes in the current social/political/economical schemes.
For questions that ask what might have happened if history had taken a different path.
different than it is in real life. This may range from small, historical changes to absolute revisions of the laws of physics.
For questions about worlds other than Earth that are significantly different. This could be a water, ice, barren or other planet. For questions about planets similar to Earth with specific differenc…
For questions regarding anything happening at a specific altitude. It is generally about the impact of high altitude.
For questions about the physical structure of an organism.
set in an era corresponding to a level of technology between the invention of writing and the fall of the Western Roman Empire in 476 AD.
the philosophical consideration that observations of the physical universe must be compatible with the conscious and sapient life that observes it.
For questions about the material composed of antiparticles (which have the opposite charge from the equivalent particles of regular matter), its uses and role in the universe, and its interaction with…
For questions dealing with events during an apocalypse scenario. Do not use for post-apocalyptic settings.
For questions about excavation of past species and civilizations, on Earth or an alien world. Topics include the actual science of archeology, information gleaned from the fossil records, and longevit…
For questions regarding the aesthetic elements of construction and design. It can apply to any historical period or complexity level, from earthen mounds to grand cathedrals.
For questions that involve outer protective coverings used for the defense of biological creatures.
For questions based on computers and other like devices having human-like intelligence.
For questions about devices that gestate, or carry fetuses, similarly to the human uterus.
refers to the act of killing someone famous or important, often for political reasons
For questions that deals with how one part of a population can assimilate the rest of it. It is mostly about cultural, linguistic or religion assimilation. Also see the society tag.