The answer is pretty simple for those who are fans of star wars and dungeons and dragons. We use these terms so much that it become more of a cool phrase to use in nerd culture. Like most things that go mainstream in which ever community, Many have forgotten the true meaning of fantasy and scifi.
When we think of fantasy we think of Lord of the Rings, elves, dwarfs and Harry Potter. When we think of Scifi we think of Star Wards and space ships and laser guns. This is much like how people get the terms geek and nerd. So today we are going to define the words fantasy and scifi. Then you can tell me your definition of the words.
Fantasy: Fantasy is anything that does not exist. At least things that we are sure that would never exist. The term fantasy is no use for scientific related stuff. Fantasy cannot be explain with science. It is much like the believe of god. We fantasy about god itself. Fantasy is related to the medieval times when witches were hunted. In fact anything related to magic can be categorize as fantasy. Creatures that have no proof of existence can be categorize as fantasy. We think of fantasy as not real. Unlike scifi we can be explained by science. The only explanation that fantasy has is spirituality. Things like reincarnation, psychics, tarot reading, wicca and other mystical practices. These things cannot be explain. They happen as if magic. A good example of this is the healing of cancer. Ever heard of those cancer patients that after ten years of cancer it suddenly disappeared from their bodies. That is a form of fantasy because not even doctors know how it happens.
Things such as the divination of elements. Being able to cast fire from ones hands. It falls in the category of fantasy. Also the worlds of fantasy have little to no technology unless its urban fantasy. Many realms of fantasy have a similar setting to that of the medieval times. Knights, sword and steel. Castles and mystical creatures. It there is no proof that is it real or possible then it is fantasy.
Fantasy has three sub genres. Dark fantasy which has a horror element to it. Epic fantasy which is set in a whole different world like Lord of the Rings and finally Urban fantasy which is set in real world locations like in Harry Potter. In Urban fantasy sometimes the character will travel from the real world to the fantasy in their story.
Scifi (Science Fiction) While many fantasy worlds in novels, video games movies and comic books are filled with magic. The worlds of Scifi rely on technology for survival and combat. Scifi is anything that can be explained by science even if it has not happened yet. The zombie apocalypse is said to be possible. Many scientist have already experimented on dead bodies, trying to animate them. Scifi is any that could be real and can be predicted by science and technology. Today’s world can be labeled as scifi to an extend. We have robotic technology, touch technology similar to the ones of movies. A wrist phone much like the ones in Star trek have already been invented by Samsung. Isn’t that crazy.
There are different types of scifi. There is urban scifi, which is when technology evolved the very world we live in. In novels and movies and video games, they use the same locations as in the real world however everything looks slightly different due to advance technology. In what I like to call High Scifi, it takes place in a different world ruled by technology.